3-carboxypropyl-aminotetralin derivatives and related compounds as mu opioid receptor antagonists

ABSTRACT

The invention provides 3-carboxypropyl-aminotetralin compounds of formula (I): 
     
       
         
         
             
             
         
       
     
     wherein R 1 , R 2 , R 3 , R 4 , R 5 , and R 6  are defined in the specification, or a pharmaceutically-acceptable salt thereof, that are antagonists at the mu opioid receptor. The invention also provides pharmaceutical compositions comprising such compounds, methods of using such compounds to treat conditions associated with mu opioid receptor activity, and processes and intermediates useful for preparing such compounds.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Nos.61/007,220, filed on Dec. 11, 2007, and 61/049,219, filed on Apr. 30,2008, the disclosures of which are incorporated herein by reference intheir entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is directed to 3-carboxypropyl-aminotetralin compoundswhich are useful as mu opioid receptor antagonists. The invention isalso directed to pharmaceutical compositions comprising such compounds,methods of using such compounds for treating or ameliorating medicalconditions mediated by mu opioid receptor activity, and processes andintermediates useful for preparing such compounds.

2. State of the Art

It is now generally understood that endogenous opioids play a complexrole in gastrointestinal physiology. Opioid receptors are expressedthroughout the body, both in the central nervous system and inperipheral regions including the gastrointestinal (GI) tract.

Compounds which function as agonists at opioid receptors, of whichmorphine is a prototypical example, are the mainstays of analgesictherapy for the treatment of moderate to severe pain. Unfortunately, useof opioid analgesics is often associated with adverse effects on the GItract, collectively termed opioid-induced bowel dysfunction (OBD). OBDincludes symptoms such as constipation, decreased gastric emptying,abdominal pain and discomfort, bloating, nausea, and gastroesophagealreflux. Both central and peripheral opioid receptors are likely involvedin the slowdown of gastrointestinal transit after opioid use. However,evidence suggests that peripheral opioid receptors in the GI tract areprimarily responsible for the adverse effects of opioids on GI function.

Since the side effects of opioids are predominantly mediated byperipheral receptors, whereas the analgesia is central in origin, aperipherally selective antagonist can potentially block undesirableGI-related side effects without interfering with the beneficial centraleffects of analgesia or precipitating central nervous system withdrawalsymptoms.

Of the three major opioid receptor subtypes, denoted mu, delta, andkappa, most clinically-used opioid analgesics are thought to act via muopioid receptor activation to exert analgesia and to alter GI motility.Accordingly, peripherally selective mu opioid antagonists are expectedto be useful for treating opioid-induced bowel dysfunction. Preferredagents will demonstrate significant binding to mu opioid receptors invitro and be active in vivo in GI animal models.

Postoperative ileus (POI) is a disorder of reduced motility of the GItract that occurs after abdominal or other surgery. The symptoms of POIare similar to those of OBD. Furthermore, since surgical patients areoften treated during and after surgery with opioid analgesics, theduration of POI may be compounded by the reduced GI motility associatedwith opioid use. Mu opioid antagonists useful for treating OBD aretherefore also expected to be beneficial in the treatment of POT.

SUMMARY OF THE INVENTION

The invention provides novel compounds that possess mu opioid receptorantagonist activity and intermediates for the preparation thereof.

Accordingly, the invention provides a compound of formula (I):

wherein

R¹ is —OR^(a) or —C(O)NR^(b)R^(c);

R², R³, and R⁴ are each independently C₁₋₃alkyl;

R⁵ is selected from C₁₋₆alkyl, phenyl, cyclohexyl, —(CH₂)₁₋₃-cyclohexyl,and —(CH₂)₁₋₃-phenyl;

R^(a), R^(b), and R^(c) are each independently hydrogen or C₁₋₃alkyl;and

R⁶ is hydrogen or C₁₋₃alkyl; and

wherein the substituents at the chiral centers marked by asterisks arein the trans configuration;

or a pharmaceutically-acceptable salt thereof.

The invention also provides a pharmaceutical composition comprising acompound of the invention and a pharmaceutically-acceptable carrier.

The invention also provides a method of treating a disease or conditionassociated with mu opioid receptor activity, e.g. a disorder of reducedmotility of the gastrointestinal tract such as opioid-induced boweldysfunction and post-operative ileus, the method comprisingadministering to the mammal, a therapeutically effective amount of acompound or of a pharmaceutical composition of the invention.

The compounds of the invention can also be used as research tools, i.e.to study biological systems or samples, or for studying the activity ofother chemical compounds. Accordingly, in another of its method aspects,the invention provides a method of using a compound of formula (I), or apharmaceutically acceptable salt thereof, as a research tool forstudying a biological system or sample or for discovering new compoundshaving mu opioid receptor activity, the method comprising contacting abiological system or sample with a compound of the invention anddetermining the effects caused by the compound on the biological systemor sample.

In separate and distinct aspects, the invention also provides syntheticprocesses and intermediates described herein, which are useful forpreparing compounds of the invention.

The invention also provides a compound of the invention as describedherein for use in medical therapy, as well as the use of a compound ofthe invention in the manufacture of a formulation or medicament fortreating a disease or condition associated with mu opioid receptoractivity, e.g. a disorder of reduced motility of the gastrointestinaltract, in a mammal.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides 3-carboxypropyl-aminotetralin mu opioid receptorantagonists of formula (I), pharmaceutically-acceptable salts thereof,and intermediates for the preparation thereof. The followingsubstituents and values are intended to provide representative examplesof various aspects of this invention. These representative values areintended to further define such aspects and are not intended to excludeother values or limit the scope of the invention.

In a specific aspect, R¹ is —OR^(a) or —C(O)NR^(b)R^(c).

In another specific aspect, R¹ is —OH or —C(O)NH₂.

In yet another specific aspect, R¹ is —C(O)NH₂.

In a specific aspect, R², R³, and R⁴ are each independently C₁₋₃alkyl.

In another specific aspect, R² and R³ are each independently methyl orethyl.

In yet other aspects, R² and R³ are each ethyl; or R² and R³ are eachmethyl.

In a specific aspect, R⁴ is methyl.

In a specific aspect, R⁵ is selected from C₁₋₆alkyl, phenyl, cyclohexyl,—(CH₂)₁₋₃-cyclohexyl, and —(CH₂)₁₋₃-phenyl.

In another specific aspect, R⁵ is selected from C₃₋₅alkyl, cyclohexyl,—(CH₂)₁₋₃-cyclohexyl, and —(CH₂)₁₋₃-phenyl. Representative R⁵ groupswithin this aspect include, but are not limited to, n-pentyl, n-butyl,2,2-dimethylpropyl, 2-methylpropyl, 1-methylethyl, cyclohexyl,cyclohexylmethyl, 4-phenylbutyl, and phenylmethyl.

In yet another specific aspect, R⁵ is cyclohexylmethyl.

In a specific aspect, R⁶ is hydrogen or C₁₋₃alkyl.

In another aspect, R⁶ is hydrogen, i.e. the compounds are carboxylicacids.

The carboxylic acids of the invention have been shown to be potentantagonists at the mu opioid receptor.

In still other aspects, R⁶ is C₁₋₃alkyl, or R⁶ is methyl, i.e. thecompounds are esters.

As described below, the esters of the invention are useful intermediatesfor the preparation of the carboxylic acids of the invention. Inaddition, the ester compounds in which R¹ is —C(O)NH₂, R² and R³ areeach ethyl, R⁴ is methyl, R⁵ is 2-methylpropyl or cyclohexylmethyl, andR⁶ is methyl have been shown to be potent antagonists at the mu opioidreceptor.

The invention further provides the compounds of Examples 1-16 herein.

The chemical naming convention used herein is illustrated for thecompound of Example 1

which is(S)-4-(2S,3S)-7-carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydronaphthalen-2-ylamino)-2-(cyclohexylmethyl)butyricacid according to the IUPAC conventions as implemented in AutoNomsoftware, (MDL Information Systems, GmbH, Frankfurt, Germany). Forconvenience, the bicyclic 1,2,3,4-tetrahydronaphthalen-2-ylamino groupis alternatively referred to herein, by the common name,“aminotetralin”.

All of the compounds of the invention are in the trans configurationwith respect to the two chiral centers indicated by asterisks in formula(I):

In addition to the stereochemistry of the aminotetralin group, thecompounds of the invention may contain a chiral center at the carbonatom to which the substituent R⁵ is attached. The compounds may be apure diastereomer, for example, the (2S),(3S) diastereomer of thecompound of Example 1 depicted above, or a mixture of the (2S),(3S)diastereomer and the (2R),(3R) diastereomer. Such diastereomericmixtures are denoted herein by the prefix trans. Accordingly, theinvention includes pure diastereomers, mixtures of diastereomers,racemic mixtures, and stereoisomer-enriched mixtures of isomers, unlessotherwise indicated. When the stereochemistry of a compound isspecified, it will be understood by those skilled in the art, that minoramounts of other stereoisomers may be present in the compositions of theinvention unless otherwise indicated, provided that any utility of thecomposition as a whole is not eliminated by the presence of such otherisomers.

In another aspect, the invention provides a compound of formula (Ia):

wherein the stereochemistry at the chiral centers is (2S),(3S) andwherein R¹, R², R³, R⁴, R⁵, and R⁶ take any of the values describedabove.

In a particular aspect, the invention provides a compound of formula(Ia) wherein:

R¹ is —C(O)NH₂;

R² and R³ are each ethyl;

R⁴ is methyl;

R⁵ is selected from C₃₋₅alkyl, cyclohexyl, —(CH₂)₁₋₃-cyclohexyl, and—(CH₂)₁₋₃-phenyl; and

R⁶ is hydrogen or methyl;

or a pharmaceutically-acceptable salt thereof.

When administered to a mammal, medical compounds are typicallytransformed in the body by metabolism to forms which can be excreted. Asdescribed in the example section below, metabolic transformation of thepresent compounds has been investigated by incubating a compound of theinvention with cryopreserved human hepatocytes and comparing theresulting metabolites with compounds of known structure. Resultsobtained support the conclusion that a principal hydroxyl metabolite ofthe compound of Example 1 is substituted with hydroxyl at the 4-positionof the cyclohexyl ring.

In yet another aspect, therefore, the invention provides a compound offormula (Ib) wherein R is hydroxyl:

wherein the compound of formula (Ib) wherein R is hydroxyl is producedin vivo by administering to a human a compound of formula (Ib) wherein Ris hydrogen.

DEFINITIONS

When describing the compounds, compositions and methods of theinvention, the following terms have the following meanings, unlessotherwise indicated.

The term “alkyl” means a monovalent saturated hydrocarbon group whichmay be linear or branched or combinations thereof. Unless otherwisedefined, such alkyl groups typically contain from 1 to 10 carbon atoms.Representative alkyl groups include, by way of example, methyl, ethyl,n-propyl (n-Pr), isopropyl (i-Pr), n-butyl (n-Bu), sec-butyl, isobutyl,tert-butyl, n-pentyl, n-hexyl, 2,2-dimethylpropyl, 2-methylbutyl,3-methylbutyl, 2-ethylbutyl, 2,2-dimethylpentyl, 2-propylpentyl, and thelike.

The term “compound” means a compound that was synthetically prepared orprepared in any other way, such as by in vivo metabolism.

The term “therapeutically effective amount” means an amount sufficientto effect treatment when administered to a patient in need of treatment.

The term “treatment” as used herein means the treatment of a disease,disorder, or medical condition in a patient, such as a mammal(particularly a human) which includes one or more of the following:

-   -   (a) preventing the disease, disorder, or medical condition from        occurring, i.e., prophylactic treatment of a patient;    -   (b) ameliorating the disease, disorder, or medical condition,        i.e., eliminating or causing regression of the disease,        disorder, or medical condition in a patient, including        counteracting the effects of other therapeutic agents;    -   (c) suppressing the disease, disorder, or medical condition,        i.e., slowing or arresting the development of the disease,        disorder, or medical condition in a patient; or    -   (d) alleviating the symptoms of the disease, disorder, or        medical condition in a patient.

The term “pharmaceutically-acceptable salt” means a salt prepared froman acid or base which is acceptable for administration to a patient,such as a mammal. Such salts can be derived frompharmaceutically-acceptable inorganic or organic acids and frompharmaceutically-acceptable bases. Typically,pharmaceutically-acceptable salts of compounds of the present inventionare prepared from acids.

Salts derived from pharmaceutically-acceptable acids include, but arenot limited to, acetic, adipic, benzenesulfonic, benzoic,camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic, glutamic,glycolic, hydrobromic, hydrochloric, lactic, maleic, malic, mandelic,methanesulfonic, mucic, nitric, oxalic, pantothenic, phosphoric,succinic, sulfuric, tartaric, p-toluenesulfonic, xinafoic(1-hydroxy-2-naphthoic acid), naphthalene-1,5-disulfonic acid and thelike.

The term “amino-protecting group” means a protecting group suitable forpreventing undesired reactions at an amino nitrogen. Representativeamino-protecting groups include, but are not limited to, formyl; acylgroups, for example alkanoyl groups, such as acetyl andtri-fluoroacetyl; alkoxycarbonyl groups, such as tert-butoxycarbonyl(Boc); arylmethoxycarbonyl groups, such as benzyloxycarbonyl (Cbz) and9-fluorenylmethoxycarbonyl (Fmoc); arylmethyl groups, such as benzyl(Bn), trityl (Tr), and 1,1-di-(4′-methoxyphenyl)methyl; silyl groups,such as trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBDMS); andthe like.

The term “hydroxy-protecting group” means a protecting group suitablefor preventing undesired reactions at a hydroxy group. Representativehydroxy-protecting groups include, but are not limited to, alkyl groups,such as methyl, ethyl, and tert-butyl; acyl groups, for example alkanoylgroups, such as acetyl; arylmethyl groups, such as benzyl (Bn),p-methoxybenzyl (PMB), 9-fluorenylmethyl (Fm), and diphenylmethyl(benzhydryl, DPM); silyl groups, such as trimethylsilyl (TMS) andtert-butyldimethylsilyl (TBS); and the like.

General Synthetic Procedures

Compounds of the invention can be prepared from readily availablestarting materials using the following general methods and procedures.Although a particular aspect of the present invention is illustrated inthe schemes below, those skilled in the art will recognize that allaspects of the present invention can be prepared using the methodsdescribed herein or by using other methods, reagents and startingmaterials known to those skilled in the art. It will also be appreciatedthat where typical or preferred process conditions (i.e., reactiontemperatures, times, mole ratios of reactants, solvents, pressures,etc.) are given, other process conditions can also be used unlessotherwise stated. Optimum reaction conditions may vary with theparticular reactants or solvent used, but such conditions can bedetermined by one skilled in the art by routine optimization procedures.

Additionally, as will be apparent to those skilled in the art,conventional protecting groups may be necessary to prevent certainfunctional groups from undergoing undesired reactions. The choice of asuitable protecting group for a particular functional group, as well assuitable conditions for protection and deprotection, are well known inthe art. For example, numerous protecting groups, and their introductionand removal, are described in T. W. Greene and G. M. Wuts, ProtectingGroups in Organic Synthesis, Third Edition, Wiley, New York, 1999, andreferences cited therein.

In a typical method of synthesis, the esters of the invention of formula(I) in which R⁶ is a C₁₋₃alkyl are prepared as shown in Scheme A. (Thesubstituents and variables shown in the following schemes have thedefinitions provided above unless otherwise indicated).

In Scheme A, intermediate (II) is reductively N-alkylated by reactionwith the aldehyde (III) to provide the product (I). The reaction istypically conducted by contacting intermediate (II) with between about 1and about 2 equivalents of an aldehyde of formula (III) in a suitableinert diluent, such as dichloromethane, methanol, or2-methyltetrahydrofuran, in the presence of between about 1 and about 5equivalents of a reducing agent. The reaction is typically conducted ata temperature in the range of about 0° C. to ambient temperature forabout a half hour to about 3 hours or until the reaction issubstantially complete. Typical reducing agents include sodiumtriacetoxyborohydride, sodium borohydride, and sodium cyanoborohydride.

The aldehyde (III) may be generated in situ from the correspondingbisulfite adduct (III′):

by reaction with a base such as sodium hydroxide immediately prior toreaction with the aminotetralin (II).

The carboxylic acids of the invention of formula (I) in which R⁶ ishydrogen are prepared from the above esters by contacting thecorresponding ester with an excess of base, for example between about 4and about 6 equivalents of a base such as sodium hydroxide in methanol.The reaction is conducted at a temperature of between about 25 and about50° C. for between about 2 and about 24 hours or until the reaction issubstantially complete.

Alternatively, a carboxylic acid of the invention can be prepared by aprocess in which a hydroxy-protecting group is used at R⁶ and whichincludes a final deprotection step, as described in Example 17 below.

An exemplary procedure for the preparation of an aminotetralinintermediate (II) in which the variable R¹ is —C(O)NH₂ is illustrated inScheme B

where P¹ represents a hydroxy-protecting group, P² represents anamino-protecting group, and —OTf represents trifluoromethane sulfonate(commonly triflate). The notation “Rac” indicates the compound is aracemic mixture of the particular structure depicted and the structurehaving the opposite stereochemistry at the chiral centers.

A small alkyl is useful as the protecting group P¹. Using an alkyl forP¹, aziridine intermediate 1, can be reacted with HBr to provideintermediate 2 which is conveniently isolated in solid form as the HBrsalt. Typically intermediate 1 is contacted with an excess, for examplebetween about 12 and about 18 equivalents, of HBr. The efficiency of thereaction is improved by inclusion of a phase transfer catalyst. Thereaction is typically conducted at a temperature between about 90 andabout 110° C. for between about 10 and about 20 hours or until thereaction is substantially complete. Using Boc, for example, for theprotecting group P², intermediate 3 is then formed by treating 2 withbase, which reforms the aziridinc ring in situ, and adding between about1 and about 1.3 equivalents of di-tert-butyldicarbonate (commonly(Boc)₂O) under conventional reaction conditions to provide intermediate3.

Alternatively, the P¹ group of aziridine intermediate 1 is deprotectedin two steps by reaction with HBr or BBr₃ and subsequent treatment withbase to provide intermediate 2a:

which is then protected at the aziridine nitrogen, for example byreaction with (Boc)₂O to provide intermediate 3.

Next, the amino-protected aziridine 3 is contacted with a large excessof an alcohol R⁴OH in the presence of a mild acid catalyst, such aspyridium tosylate to provide intermediate 4.

An aminotetralin intermediate of formula (II) in which R¹ is —OH can beprepared by deprotection of intermediate 4. For example, when theprotecting group P² is Boc, the phenol intermediate of formula (II) isobtained by treating 4 with an acid. Similarly, an aminotetralinintermediate of formula (II) in which R¹ is —OR^(a) where R^(a) isC₁₋₃alkyl, can be prepared analogously starting with an intermediate offormula 1 in which P¹ is the desired small alkyl and omitting theinitial deprotection step.

The remainder of the steps in Scheme B depict the conversion of thehydroxy substituted aminotetralin 4 to a carboxamide substitutedintermediate 7 and a final deprotection step. The hydroxyl ofintermediate 4 is first converted to the triflate by contacting 4 in aninert diluent with between about 1 and about 2 equivalents oftrifluoromethane sulfonylchloride in the presence of between about 1 andabout 3 equivalents of base, such as triethylamine to provideintermediate 5. Reaction of 5 with zinc cyanide in the presence of atransition metal catalyst, provides intermediate 6. This reaction istypically conducted at a temperature between about 80° C. and 120° C.under an inert atmosphere for about one half to about 2 hours or untilthe reaction is substantially complete.

Next, the nitrile of intermediate 6 is hydrolyzed to the carboxamide ofintermediate 7. As described in the examples below, in one method ofsynthesis, the nitrile 6 is contacted with between about 5 and about 8equivalents of sodium perborate monohydrate in an inert diluent such asmethanol. The reaction is conducted at a temperature between about 50and about 60° C. for about 12 to about 24 hours or until the reaction issubstantially complete. Alternative processes for hydrolysis of anitrile to an amide include use of a platinum catalyst, in particular,hydrido(dimethylphosphoniousacid-kP)[hydrogenbis(dimethylphosphinito-kP)]platinum(II), and treatment with hydrogenperoxide, as described in examples below. Finally, intermediate 7 isdeprotected by conventional treatment with an acid to provide theaminotetralin of formula (II).

An intermediate of formula (II) in which R¹ is —C(O)NR^(b)R^(c) whereR^(b) and R^(c) are alkyl can be prepared from intermediate 6 byconverting the nitrile to a carboxylic acid by hydrolysis in thepresence of a base followed by amide coupling with an amine of theformula HNR^(b)R^(c).

The individual enantiomers of formula (II) can be separated using achiral auxiliary. Scheme C illustrates use of the chiral auxiliarycarbonic acid 4-nitro-phenyl ester (R)-1-phenyl-ethyl ester (8):

to prepare a pair of non-racemic diastereomers 9a and 9b that can beseparated. The notation “Abs” denotes the specific chiral compoundshown. The racemic aminotetralin (II) is contacted with between about0.8 and about 1.2 equivalents of chiral auxiliary 8 in an inert diluentin the presence of between about 2 and about 4 equivalents of a base,such as triethylamine to prepare a diastereomeric mixture ofintermediates 9a and 9b. The reaction is typically conducted at atemperature between about 80 and about 95° C. for between about 4 andabout 20 hours or until the reaction is substantially complete. Thediastereomers 9a and 9b can be separated by high performance liquidchromatography (HPLC) and collected separately or by crystallization inwhich the diastereomer 9a crystallized preferentially, leavingpredominantly the diastereomer 9b in solution. Finally, the carbamategroup can be removed from the isolated 9a and 9b diastereomers bytreatment with an acid to provide the individual enantiomers ofaminotetralin (II). The chiral auxiliary 8 can be prepared by reactionof (R)-1-phenylethanol with p-nitrophenyl chloroformate as described inthe examples below.

The aziridine intermediate 1 used in Scheme B can be obtained byreacting a substituted 3,4-dihydro-1H-naphthalen-2-one:

with an alkyl halide to add the alkyl substituents R² and R³ at the2-position, treatment with a hydroxylamine salt to convert the carboxyto an oxime and subsequent treatment with lithium aluminum hydride orother reducing agent to convert the oxime to the aziridine 1, asdescribed, for example, in U.S. Pat. No. 6,844,368 and in Preparation14, below.

The aldehyde (III) used in Scheme A is conveniently prepared from thecorresponding carboxylic acid 10 as shown in Scheme D:

where R⁶ represents a C₁₋₃alkyl. Borane reduction of the carboxylic acid10 provides the alcohol 11. The reaction is typically conducted bycontacting acid 10 with about 2 equivalents of a boranc-tetrahydrofurancomplex in tetrahydrofuran at a temperature between about −5 and about0° C. The alcohol 11 is then oxidized to the aldehyde (III). Usefuloxidizing reagents include dimethylsulfoxide activated by a sulfurtrioxide pyridine complex and sodium hypochlorite with a2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) catalyst. If desired, thealcohol 11 can be converted to the bisulfite adduct (III′) withoutisolation of the aldehyde (III) by addition of sodium bisulfite afterthe oxidation step.

Further details regarding specific reaction conditions and otherprocedures for preparing representative compounds of the invention orintermediates thereto are described in the examples below.

Accordingly, in a method aspect, the invention provides a process forpreparing a compound of formula (I), or a salt thereof, the processcomprising (a) reacting a compound of formula (II) with a compound offormula (III), wherein R⁶ is C₁₋₃alkyl, and, (b) when R⁶ is hydrogen,contacting the product of step (a) with an excess of base to provide acompound of formula (I), or a salt thereof.

In yet other aspects, the invention provides the novel intermediate offormula 2 or a hydrobromide salt thereof and a process for thepreparation of the hydrobromide salt of compound 2 in solid form, theprocess comprising reacting a compound of formula 1 with HBr andisolating the product in solid form.

Pharmaceutical Compositions

The 3-carboxypropyl-aminotetralin compounds of the invention aretypically administered to a patient in the form of a pharmaceuticalcomposition or formulation. Such pharmaceutical compositions may beadministered to the patient by any acceptable route of administrationincluding, but not limited to, oral, rectal, vaginal, nasal, inhaled,topical (including transdermal) and parenteral modes of administration.

Accordingly, in one of its compositions aspects, the invention isdirected to a pharmaceutical composition comprising apharmaceutically-acceptable carrier or excipient and a therapeuticallyeffective amount of a compound of formula (I) or a pharmaceuticallyacceptable salt thereof. Optionally, such pharmaceutical compositionsmay contain other therapeutic and/or formulating agents if desired. Whendiscussing compositions, the “compound of the invention” may also bereferred to herein as the “active agent”. As used herein, the term“compound of the invention” is intended to include compounds of formula(I) as well as the species embodied in formula (Ia). “Compound of theinvention” includes, in addition, pharmaceutically-acceptable salts andsolvates of the compound unless otherwise indicated.

The pharmaceutical compositions of the invention typically contain atherapeutically effective amount of a compound of the present inventionor a pharmaceutically-acceptable salt thereof. Those skilled in the artwill recognize, however, that a pharmaceutical composition may containmore than a therapeutically effective amount, i.e., bulk compositions,or less than a therapeutically effective amount, i.e., individual unitdoses designed for multiple administration to achieve a therapeuticallyeffective amount.

Typically, such pharmaceutical compositions will contain from about 0.1to about 95% by weight of the active agent; preferably, from about 5 toabout 70% by weight; and more preferably from about 10 to about 60% byweight of the active agent.

Any conventional carrier or excipient may be used in the pharmaceuticalcompositions of the invention. The choice of a particular carrier orexcipient, or combinations of carriers or excipients, will depend on themode of administration being used to treat a particular patient or typeof medical condition or disease state. In this regard, the preparationof a suitable pharmaceutical composition for a particular mode ofadministration is well within the scope of those skilled in thepharmaceutical arts. Additionally, the carriers or excipients used inthe pharmaceutical compositions of this invention arecommercially-available. By way of further illustration, conventionalformulation techniques are described in Remington: The Science andPractice of Pharmacy, 20^(th) Edition, Lippincott Williams & White,Baltimore, Md. (2000); and H. C. Ansel et al., Pharmaceutical DosageForms and Drug Delivery Systems, 7^(th) Edition, Lippincott Williams &White, Baltimore, Md. (1999).

Representative examples of materials which can serve as pharmaceuticallyacceptable carriers include, but are not limited to, the following:sugars, such as lactose, glucose and sucrose; starches, such as cornstarch and potato starch; cellulose, such as microcrystalline cellulose,and its derivatives, such as sodium carboxymethyl cellulose, ethylcellulose and cellulose acetate; powdered tragacanth; malt; gelatin;talc; excipients, such as cocoa butter and suppository waxes; oils, suchas peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil,corn oil and soybean oil; glycols, such as propylene glycol; polyols,such as glycerin, sorbitol, mannitol and polyethylene glycol; esters,such as ethyl oleate and ethyl laurate; agar; buffering agents, such asmagnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-freewater; isotonic saline; Ringer's solution; ethyl alcohol; phosphatebuffer solutions; and other non-toxic compatible substances employed inpharmaceutical compositions.

Pharmaceutical compositions are typically prepared by thoroughly andintimately mixing or blending the active agent with apharmaceutically-acceptable carrier and one or more optionalingredients. The resulting uniformly blended mixture can then be shapedor loaded into tablets, capsules, pills and the like using conventionalprocedures and equipment.

The pharmaceutical compositions of the invention are preferably packagedin a unit dosage form. The term “unit dosage form” refers to aphysically discrete unit suitable for dosing a patient, i.e., each unitcontaining a predetermined quantity of active agent calculated toproduce the desired therapeutic effect either alone or in combinationwith one or more additional units. For example, such unit dosage formsmay be capsules, tablets, pills, and the like, or unit packages suitablefor parenteral administration.

In one embodiment, the pharmaceutical compositions of the invention aresuitable for oral administration. Suitable pharmaceutical compositionsfor oral administration may be in the form of capsules, tablets, pills,lozenges, cachets, dragees, powders, granules; or as a solution or asuspension in an aqueous or non-aqueous liquid; or as an oil-in-water orwater-in-oil liquid emulsion; or as an elixir or syrup; and the like;each containing a predetermined amount of a compound of the presentinvention as an active ingredient.

When intended for oral administration in a solid dosage form (i.e., ascapsules, tablets, pills and the like), the pharmaceutical compositionsof the invention will typically comprise the active agent and one ormore pharmaceutically-acceptable carriers, such as sodium citrate ordicalcium phosphate. Optionally or alternatively, such solid dosageforms may also comprise: fillers or extenders, such as starches,microcrystal line cellulose, lactose, sucrose, glucose, mannitol, and/orsilicic acid; binders, such as carboxymethylcellulose, alginates,gelatin, polyvinyl pyrrolidone, sucrose and/or acacia; humectants, suchas glycerol; disintegrating agents, such as agar-agar, calciumcarbonate, potato or tapioca starch, alginic acid, certain silicates,and/or sodium carbonate; solution retarding agents, such as paraffin;absorption accelerators, such as quaternary ammonium compounds; wettingagents, such as cetyl alcohol and/or glycerol monostearate; absorbents,such as kaolin and/or bentonite clay; lubricants, such as talc, calciumstearate, magnesium stearate, solid polyethylene glycols, sodium laurylsulfate, and/or mixtures thereof; coloring agents; and buffering agents.

Release agents, wetting agents, coating agents, sweetening, flavoringand perfuming agents, preservatives and antioxidants can also be presentin the pharmaceutical compositions of the invention. Examples ofpharmaceutically-acceptable antioxidants include: water-solubleantioxidants, such as ascorbic acid, cysteine hydrochloride, sodiumbisulfate, sodium metabisulfate, sodium sulfite and the like;oil-soluble antioxidants, such as ascorbyl palmitate, butylatedhydroxyanisole, butylated hydroxytoluene, lecithin, propyl gallate,alpha-tocopherol, and the like; and metal-chelating agents, such ascitric acid, ethylenediamine tetraacetic acid, sorbitol, tartaric acid,phosphoric acid, and the like. Coating agents for tablets, capsules,pills and like, include those used for enteric coatings, such ascellulose acetate phthalate, polyvinyl acetate phthalate, hydroxypropylmethylcellulose phthalate, methacrylic acid-methacrylic acid estercopolymers, cellulose acetate trimellitate, carboxymethyl ethylcellulose, hydroxypropyl methyl cellulose acetate succinate, and thelike.

Pharmaceutical compositions of the invention may also be formulated toprovide slow or controlled release of the active agent using, by way ofexample, hydroxypropyl methyl cellulose in varying proportions; or otherpolymer matrices, liposomes and/or microspheres. In addition, thepharmaceutical compositions of the invention may optionally containopacifying agents and may be formulated so that they release the activeingredient only, or preferentially, in a certain portion of thegastrointestinal tract, optionally, in a delayed manner. Examples ofembedding compositions which can be used include polymeric substancesand waxes. The active agent can also be in micro-encapsulated form, ifappropriate, with one or more of the above-described excipients.

Suitable liquid dosage forms for oral administration include, by way ofillustration, pharmaceutically-acceptable emulsions, microemulsions,solutions, suspensions, syrups and elixirs. Liquid dosage formstypically comprise the active agent and an inert diluent, such as, forexample, water or other solvents, solubilizing agents and emulsifiers,such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethylacetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butyleneglycol, oils (esp., cottonseed, groundnut, corn, germ, olive, castor andsesame oils), glycerol, tetrahydrofuryl alcohol, polyethylene glycolsand fatty acid esters of sorbitan, and mixtures thereof. Suspensions, inaddition to the active ingredient, may contain suspending agents suchas, for example, ethoxylated isostearyl alcohols, polyoxyethylenesorbitol and sorbitan esters, microcrystalline cellulose, aluminummetahydroxide, bentonite, agar-agar and tragacanth, and mixturesthereof.

The compounds of this invention can also be administered parenterally(e.g. by intravenous, subcutaneous, intramuscular or intraperitonealinjection). For parenteral administration, the active agent is typicallyadmixed with a suitable vehicle for parenteral administration including,by way of example, sterile aqueous solutions, saline, low molecularweight alcohols such as propylene glycol, polyethylene glycol, vegetableoils, gelatin, fatty acid esters such as ethyl oleate, and the like.Parenteral formulations may also contain one or more anti-oxidants,solubilizers, stabilizers, preservatives, wetting agents, emulsifiers,buffering agents, or dispersing agents. These formulations may berendered sterile by use of a sterile injectable medium, a sterilizingagent, filtration, irradiation, or heat.

Alternatively, the pharmaceutical compositions of the invention areformulated for administration by inhalation. Suitable pharmaceuticalcompositions for administration by inhalation will typically be in theform of an aerosol or a powder. Such compositions are generallyadministered using well-known delivery devices, such as a metered-doseinhaler, a dry powder inhaler, a nebulizer or a similar delivery device.

When administered by inhalation using a pressurized container, thepharmaceutical compositions of the invention will typically comprise theactive ingredient and a suitable propellant, such asdichlorodifluoromethane, trichlorofluoromethane,dichlorotetrafluoroethane, carbon dioxide or other suitable gas.Additionally, the pharmaceutical composition may be in the form of acapsule or cartridge (made, for example, from gelatin) comprising acompound of the invention and a powder suitable for use in a powderinhaler. Suitable powder bases include, by way of example, lactose orstarch.

The compounds of the invention can also be administered transdermallyusing known transdermal delivery systems and excipients. For example,the active agent can be admixed with permeation enhancers, such aspropylene glycol, polyethylene glycol monolaurate, azacycloalkan-2-onesand the like, and incorporated into a patch or similar delivery system.Additional excipients including gelling agents, emulsifiers and buffers,may be used in such transdermal compositions if desired.

If desired, the compounds of this invention may be administered incombination with one or more other therapeutic agents. In thisembodiment, a compound of this invention is either physically mixed withthe other therapeutic agent to form a composition containing bothagents; or each agent is present in separate and distinct compositionswhich are administered to the patient simultaneously or sequentially inany order.

For example, a compound of formula I can be combined with secondtherapeutic agent using conventional procedures and equipment to form acomposition comprising a compound of formula I and a second therapeuticagent. Additionally, the therapeutic agents may be combined with apharmaceutically acceptable carrier to form a pharmaceutical compositioncomprising a compound of formula I, a second therapeutic agent and apharmaceutically acceptable carrier. In this embodiment, the componentsof the composition are typically mixed or blended to create a physicalmixture. The physical mixture is then administered in a therapeuticallyeffective amount using any of the routes described herein.

Alternatively, the therapeutic agents may remain separate and distinctbefore administration to the patient. In this embodiment, the agents arenot physically mixed together before administration but are administeredsimultaneously or at separate times as separate compositions. Whenadministered separately, the agents are administered sufficiently closein time so as to provide a desired therapeutic effect. Such compositionscan be packaged separately or may be packaged together as a kit. The twotherapeutic agents in the kit may be administered by the same route ofadministration or by different routes of administration.

In particular, the compounds of the invention can be combined withopioid analgesic therapeutic agents. As described above, use of opioidanalgesics is often associated with undesirable side effects such as,for example, constipation, decreased gastric emptying, abdominal pain,bloating, nausea, and gastroesophageal reflux. These adverse effects maybe sufficiently severe to limit the dose of opioid analgesic that can bedelivered to a patient to a suboptimal level. Coadministration of acompound of the invention with an opioid is likely to reduce or preventside effects, thereby increasing the utility of the analgesic agent forpain alleviation.

Opioid analgesics that may be used in combination with compounds of thepresent invention include, but are not limited to, morphine,hydromorphone, oxymorphone, pethidine, codeine, dihydrocodeine,oxycontin, oxycodone, hydrocodone, sufentanil, fentanyl, remifentanil,buprenorphine, butorphanol, tramadol, methadone, heroin, propoxyphene,meperidine, levorphenol, pentazocine, and combinations of opioidanalgesics with ibuprofen or acetaminophen. Compounds of the inventioncould be used in doses ranging from about 0.05 to about 100 mg per dayfor an average 70 kg patient, when combined with an opioid analgesic atits therapeutic dose, for example, when combined with oxycodone at adose of between about 5 mg and about 160 mg per day.

In addition, prokinetic agents acting via mechanisms other than muopioid receptor antagonism may be used in combination with the presentcompounds. For example, 5-HT₄ receptor agonists, such as tegaserod,renzapride, mosapride, prucalopride,1-isopropyl-1H-indazole-3-carboxylic acid{(1S,3R,5R)-8-[2-(4-acetylpiperazin-1-yl)ethyl]-8-azabicyclo[3.2.1]oct-3-yl}amide,1-isopropyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid{(1S,3R,5R)-8-[(R)-2-hydroxy-3-(methanesulfonyl-methyl-amino)propyl]-8-azabicyclo[3.2.1]oct-3-yl}amide,or4-(4-{[(2-isopropyl-1H-benzoimidazole-4-carbonyl)amino]methyl}-piperidin-1-ylmethyl)piperidine-1-carboxylicacid methyl ester may be used as the second therapeutic agent.

Additional useful prokinetic agents include, but are not limited to,5-HT₃ receptor agonists (e.g. pumosetrag), 5-HT_(1A) receptorantagonists (e.g. AGI 001), alpha-2-delta ligands (e.g. PD-217014),chloride channel openers (e.g. lubiprostone), dopamine antagonists (e.g.itopride, metaclopramide, domperidone), GABA-B agonists (e.g. baclofen,AGI 006), kappa opioid agonists (e.g. asimadoline), muscarinic M₁ and M₂antagonists (e.g. acotiamide), motilin agonists (e.g. mitemcinal),guanylate cyclase activators (e.g. MD-1100) and ghrelin agonists (e.g.Tzp 101, RC 1139).

Numerous additional examples of such therapeutic agents are known in theart and any such known therapeutic agents may be employed in combinationwith the compounds of this invention. Secondary agent(s), when included,are present in a therapeutically effective amount, i.e. in any amountthat produces a therapeutically beneficial effect when co-administeredwith a compound of the invention. Suitable doses for the othertherapeutic agents administered in combination with a compound of theinvention are typically in the range of about 0.05 μg/day to about 100mg/day.

Accordingly, the pharmaceutical compositions of the invention optionallyinclude a second therapeutic agent as described above.

The following examples illustrate representative pharmaceuticalcompositions of the present invention:

Formulation Example A Hard Gelatin Capsules for Oral Administration

A compound of the invention (50 g), spray-dried lactose (200 g) andmagnesium stearate (10 g) are thoroughly blended. The resultingcomposition is loaded into a hard gelatin capsule (260 mg of compositionper capsule).

Formulation Example B Hard Gelatin Capsules for Oral Administration

A compound of the invention (20 mg), starch (89 mg), microcrystallinecellulose (89 mg), and magnesium stearate (2 mg) are thoroughly blendedand then passed through a No. 45 mesh U.S. sieve. The resultingcomposition is loaded into a hard gelatin capsule (200 mg of compositionper capsule).

Formulation Example C Gelatin Capsules for Oral Administration

A compound of the invention (10 mg), polyoxyethylene sorbitan monooleate(50 mg), and starch powder (250 mg) are thoroughly blended and thenloaded into a gelatin capsule (310 mg of composition per capsule).

Formulation Example D Tablets for Oral Administration

A compound of the invention (5 mg), starch (50 mg), and microcrystallinecellulose (35 mg) are passed through a No. 45 mesh U.S. sieve and mixedthoroughly. A solution of polyvinylpyrrolidone (10 wt % in water, 4 mg)is mixed with the resulting powders, and this mixture is then passedthrough a No. 14 mesh U.S. sieve. The granules so produced are dried at50-60° C. and passed through a No. 18 mesh U.S. sieve. Sodiumcarboxymethyl starch (4.5 mg), magnesium stearate (0.5 mg) and talc (1mg), which have previously been passed through a No. 60 mesh U.S. sieve,are then added to the granules. After mixing, the mixture is compressedon a tablet machine to afford a tablet weighing 100 mg.

Formulation Example E Tablets for Oral Administration

A compound of the invention (25 mg), microcrystalline cellulose (400mg), fumed silicon dioxide (10 mg), and stearic acid (5 mg) arethoroughly blended and then compressed to form tablets (440 mg ofcomposition per tablet).

Formulation Example F Single-Scored Tablets for Oral Administration

A compound of the invention (15 mg), cornstarch (50 mg), croscarmellosesodium (25 mg), lactose (120 mg), and magnesium stearate (5 mg) arethoroughly blended and then compressed to form single-scored tablet (215mg of compositions per tablet).

Formulation Example G Suspension for Oral Administration

The following ingredients are thoroughly mixed to form a suspension fororal administration containing 100 mg of active ingredient per 10 mL ofsuspension:

Ingredients Amount Compound of the invention 0.1 g Fumaric acid 0.5 gSodium chloride 2.0 g Methyl paraben 0.15 g Propyl paraben 0.05 gGranulated sugar 25.5 g Sorbitol (70% solution) 12.85 g Veegum k(Vanderbilt Co.) 1.0 g Flavoring 0.035 mL Colorings 0.5 mg Distilledwater q.s. to 100 mL

Formulation Example H Dry Powder Composition

A micronized compound of the invention (1 mg) is blended with lactose(25 mg) and then loaded into a gelatin inhalation cartridge. Thecontents of the cartridge are administered using a powder inhaler.

Formulation Example J Injectable Formulation

A compound of the invention (0.1 g) is blended with 0.1 M sodium citratebuffer solution (15 mL). The pH of the resulting solution is adjusted topH 6 using 1 N aqueous hydrochloric acid or 1 N aqueous sodiumhydroxide. Sterile normal saline in citrate buffer is then added toprovide a total volume of 20 mL.

Formulation Example K Single-Scored Tablets for Oral Administration

A compound of the invention (10 mg), oxycodone hydrochloride (10 mg),cornstarch (50 mg), croscarmellose sodium (25 mg), lactose (120 mg), andmagnesium stearate (5 mg) are thoroughly blended and then compressed toform single-scored tablet (220 mg of compositions per tablet).

Formulation Example L Injectable Formulation

A compound of the invention (0.1 g) and oxycodone hydrochloride (0.1 g)are blended with 0.1 M sodium citrate buffer solution (15 mL). The pH ofthe resulting solution is adjusted to pH 6 using 1 N aqueoushydrochloric acid or 1 N aqueous sodium hydroxide. Sterile normal salinein citrate buffer is then added to provide a total volume of 20 mL.

It will be understood that any form of the compounds of the invention,(i.e. free base, pharmaceutical salt, or solvate) that is suitable forthe particular mode of administration, can be used in the pharmaceuticalcompositions discussed above.

Utility

The 3-carboxypropyl-aminotetralin compounds of the invention areantagonists at the mu opioid receptor and therefore are expected to beuseful for treating medical conditions mediated by mu opioid receptorsor associated with mu opioid receptor activity, i.e. medical conditionswhich are ameliorated by treatment with a mu opioid receptor antagonist.In particular, the compounds of the invention are expected to be usefulfor treating adverse effects associated with use of opioid analgesics,i.e. symptoms such as constipation, decreased gastric emptying,abdominal pain, bloating, nausea, and gastroesophageal reflux, termedcollectively opioid-induced bowel dysfunction. The mu opioid receptorantagonists of the invention are also expected to be useful for treatingpost-operative ileus, a disorder of reduced motility of thegastrointestinal tract that occurs after abdominal or other surgery. Inaddition, it has been suggested that mu opioid receptor antagonistcompounds may be used for reversing opioid-induced nausea and vomiting.Further, those mu opioid receptor antagonists exhibiting some centralpenetration may be useful in the treatment of dependency on, oraddiction to, narcotic drugs, alcohol, or gambling, or in preventing,treating, and/or ameliorating obesity.

Since compounds of the invention increase motility of thegastrointestinal (GI) tract in animal models, the compounds are expectedto be useful for treating disorders of the GI tract caused by reducedmotility in mammals, including humans. Such GI motility disordersinclude, by way of illustration, chronic constipation,constipation-predominant irritable bowel syndrome (C-IBS), diabetic andidiopathic gastroparesis, and functional dyspepsia.

In one aspect, therefore, the invention provides a method of increasingmotility of the gastrointestinal tract in a mammal, the methodcomprising administering to the mammal a therapeutically effectiveamount of a pharmaceutical composition comprising apharmaceutically-acceptable carrier and a compound of the invention.

When used to treat disorders of reduced motility of the GI tract orother conditions mediated by mu opioid receptors, the compounds of theinvention will typically be administered orally in a single daily doseor in multiple doses per day, although other forms of administration maybe used. For example, particularly when used to treat post-operativeileus, the compounds of the invention may be administered parenterally.The amount of active agent administered per dose or the total amountadministered per day will typically be determined by a physician, in thelight of the relevant circumstances, including the condition to betreated, the chosen route of administration, the actual compoundadministered and its relative activity, the age, weight, and response ofthe individual patient, the severity of the patient's symptoms, and thelike.

Suitable doses for treating disorders of reduced motility of the GItract or other disorders mediated by mu opioid receptors will range fromabout 0.0007 to about 20 mg/kg/day of active agent, including from about0.0007 to about 1.4 mg/kg/day. For an average 70 kg human, this wouldamount to from about 0.05 to about 100 mg per day of active agent.

In one aspect of the invention, the compounds of the invention are usedto treat opioid-induced bowel dysfunction. When used to treatopioid-induced bowel dysfunction, the compounds of the invention willtypically be administered orally in a single daily dose or in multipledoses per day. Preferably, the dose for treating opioid-induced boweldysfunction will range from about 0.05 to about 100 mg per day.

In another aspect of the invention, the compounds of the invention areused to treat post-operative ileus. When used to treat post-operativeileus, the compounds of the invention will typically be administeredorally or intravenously in a single daily dose or in multiple doses perday. Preferably, the dose for treating post-operative ileus will rangefrom about 0.05 to about 100 mg per day.

The invention also provides a method of treating a mammal having adisease or condition associated with mu opioid receptor activity, themethod comprising administering to the mammal a therapeuticallyeffective amount of a compound of the invention or of a pharmaceuticalcomposition comprising a compound of the invention.

As described above, compounds of the invention are mu opioid receptorantagonists. The invention further provides, therefore, a method ofantagonizing a mu opioid receptor in a mammal, the method comprisingadministering a compound of the invention to the mammal.

The mu opioid receptor antagonists of the invention are optionallyadministered in combination with another therapeutic agent or agents, inparticular, in combination with opioid analgesics or with prokineticagents acting via non-mu opioid mechanisms. Accordingly, in anotheraspect, the methods and compositions of the invention further comprise atherapeutically effective amount of an opioid analgesic or anotherprokinetic agent. The methods of the invention include, for example, amethod of reducing or preventing a side effect associated with use of anopioid agent in a mammal, the method comprising administering to themammal an opioid agent and a compound of the invention.

In addition, the compounds of the invention are also useful as researchtools for investigating or studying biological systems or samples havingmu opioid receptors, or for discovering new compounds having mu opioidreceptor activity. Any suitable biological system or sample having muopioid receptors may be employed in such studies which may be conductedeither in vitro or in vivo. Representative biological systems or samplessuitable for such studies include, but are not limited to, cells,cellular extracts, plasma membranes, tissue samples, mammals (such asmice, rats, guinea pigs, rabbits, dogs, pigs, etc.) and the like. Theeffects of contacting a biological system or sample comprising a muopioid receptor with a compound of the invention are determined usingconventional procedures and equipment, such as the radioligand bindingassay and functional assay described herein or other functional assaysknown in the art. Such functional assays include, but are not limitedto, ligand-mediated changes in intracellular cyclic adenosinemonophosphate (cAMP), ligand-mediated changes in activity of the enzymeadenylyl cyclase, ligand-mediated changes in incorporation of analogs ofguanosine triphosphate (GTP), such as [³⁵S]GTPγS (guanosine5′-O-(γ-thio)triphosphate) or GTP-Eu, into isolated membranes viareceptor catalyzed exchange of GTP analogs for GDP analogs, andligand-mediated changes in free intracellular calcium ions. A suitableconcentration of a compound of the invention for such studies typicallyranges from about 1 nanomolar to about 500 nanomolar.

When using compounds of the invention as research tools for discoveringnew compounds have mu opioid receptor activity, binding or functionaldata for a test compound or a group of test compounds is compared to themu opioid receptor binding or functional data for a compound of theinvention to identify test compounds that have superior binding orfunctional activity, if any. This aspect of the invention includes, asseparate embodiments, both the generation of comparison data (using theappropriate assays) and the analysis of the test data to identify testcompounds of interest.

Among other properties, compounds of the invention have been found toexhibit potent binding to mu opioid receptors and little or no agonismin mu receptor functional assays. Therefore, the compounds of theinvention are potent mu opioid receptor antagonists. Further, compoundsof the invention have demonstrated predominantly peripheral activity ascompared with central nervous system activity in animal models.Therefore, these compounds can be expected to reverse opioid-inducedreductions in GI motility without interfering with the beneficialcentral effects of analgesia. These properties, as well as the utilityof the compounds of the invention, can be demonstrated using various invitro and in vivo assays well-known to those skilled in the art.Representative assays are described in further detail in the followingexamples.

EXAMPLES

The following synthetic and biological examples are offered toillustrate the invention, and are not to be construed in any way aslimiting the scope of the invention. In the examples below, thefollowing abbreviations have the following meanings unless otherwiseindicated. Abbreviations not defined below have their generally acceptedmeanings

-   -   ACN=acetonitrile    -   AcOH=acetic acid    -   Boc=tert-butoxycarbonyl    -   (Boc)₂O=di-tert-butyl dicarbonate    -   DCM=dichloromethane    -   DIPEA=N,N-diisopropylethylamine    -   DMF=N,N-dimethylformamide    -   DMSO=dimethyl sulfoxide    -   EtOAc=ethyl acetate    -   EtOH=ethanol    -   HATU=N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)uronium        hexafluorophosphate    -   MeOH=methanol    -   MeTHF=2-methyl-tetrahydrofuran    -   MTBE=methyl tert-butyl ether    -   RT=room temperature    -   TFA=trifluoroacetic acid    -   THF=tetrahydrofuran

Reagents and solvents were purchased from commercial suppliers (Aldrich,Fluka, Sigma, etc.), and used without further purification. Reactionswere run under nitrogen atmosphere, unless noted otherwise. Progress ofreaction mixtures was monitored by thin layer chromatography (TLC),analytical high performance liquid chromatography (anal. HPLC), and massspectrometry. Reaction mixtures were worked up as described specificallyin each reaction; commonly they were purified by extraction and otherpurification methods such as temperature-, and solvent-dependentprecipitation. In addition, reaction mixtures were routinely purified bypreparative HPLC, typically using Microsorb C18 and Microsorb BDS columnpackings and conventional eluents. Characterization of reaction productswas routinely carried out by mass and ¹H-NMR spectrometry. For NMRmeasurement, samples were dissolved in deuterated solvent (CD₃OD, CDCl₃,or DMSO-d₆), and ¹H-NMR spectra were acquired with a Varian Gemini 2000instrument (400 MHz) under standard observation conditions. Massspectrometric identification of compounds was performed by anelectrospray ionization method (ESMS) with an Applied Biosystems (FosterCity, Calif.) model API 150 EX instrument or an Agilent (Palo Alto,Calif.) model 1200 LC/MSD instrument.

Preparation 1:7,7-diethyl-5-hydroxy-1a,2,7,7a-tetrahydro-1-aza-cyclopropa[b]naphthalene-1-carboxylicacid tert-butyl ester a.7-Amino-6-bromo-8,8-diethyl-5,6,7,8-tetrahydronaphthalen-2-olhydrobromide

To a flask was added7,7-diethyl-5-methoxy-1a,2,7,7a-tetrahydro-1H-1-aza-cyclopropa[b]naphthalene(268 g, 1.16 mol) and hydrogen bromide (1.97 L, 17.38 mol), followed bytetra-N-butylammonium bromide (38 g, 0.12 mol). The reaction mixture washeated at 100° C. overnight with stirring, cooled to room temperatureand then poured into stirred ethyl acetate (2.5 L). The product wasisolated by filtration, the filter cake was washed with ethyl acetate(2×200 mL) and dried to yield crude product (370 g) as a purplish solid.The crude product was suspended in ethanol (1.50 L) then heated at 80°C. for 30 min. The resulting slurry was cooled to room temperature over1 h, and filtered. The flask and filter cake with were washed withethanol (2×100 mL) and then with ethyl acetate (100 mL) and driedovernight to yield the title compound as a solid. (275 g, ˜96% purity).

b. 7,7-Diethyl-5-hydroxy-1a,2,7,7a-tetrahydro-1-aza-cyclopropa[b]naphthalene-1-carboxylicacid tert-butyl ester

To a slurry of7-amino-6-bromo-8,8-diethyl-5,6,7,8-tetrahydronaphthalen-2-olhydrobromide (20.0 g, 52.8 mmol) and ethyl acetate (200 mL) was added1.0 M sodium hydroxide in water (106 mL). The reaction mixture wasstirred at 25° C. for 2 h, di-tert-butyldicarbonate (15 g, 68 mmol) inethyl acetate (5 mL) was added and the reaction mixture was stirred atroom temperature for 2 h. Following removal of two-thirds of the ethylacetate (135 mL), heptane (135 mL) was added and the resulting slurrywas stirred at room temperature over 30 min and then at 5° C. overnight.The slurry was filtered, and the filter cake was rinsed with water (100mL), rinsed with heptane (50 mL), and dried under vacuum to give thetitle compound (14.3 g).

Preparation 2:trans-(7-Cyano-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester a.trans-(1,1-Diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester

To a slurry of7,7-diethyl-5-hydroxy-1a,2,7,7a-tetrahydro-1-aza-cyclopropa[b]naphthalene-1-carboxylicacid tert-butyl ester (170.0 g, 535.6 mmol) and methanol (1700 mL) wasadded pyridinium p-toluenesulfonate (13.4 g, 53.6 mmol) and the reactionmixture was stirred at 40° C. for 4 h. The volume was reduced by rotaryevaporation to ˜300 mL resulting in a thick white slurry. The productwas isolated by filtration; the filter cake was washed with coldmethanol (50 mL) and dried in air for 3 h to yield the title compound(150 g). The filtrate was reduced to ˜50 mL and stirred at 0° C. for 2h, filtered, and dried to yield additional product (25 g).

b. trans-Trifluoro-methanesulfonic acid7-tert-butoxycarbonylamino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-ylester

A mixture oftrans-(1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester (195.0 g, 0.558 mol), triethylamine (160 mL, 1.1mol) and ethyl acetate (2000 mL) was stirred at room temperature for 15min and cooled to 0° C. followed by slow addition oftrifluoro-methanesulfonyl chloride (150 g, 0.89 mol) keeping theinternal temperature below 4° C. The resulting slurry was stirred at 0°C. for 1 h. Additional triethylamine (16 mL) followed by additionaltrifluoromethanesulfonyl chloride (15.0 g) was added slowly maintaininga temperature below 5° C. The reaction mixture was stirred at roomtemperature for an additional hour. Diluted brine (1.0 L) was added andthe reaction mixture was stirred for 10 min at room temperature. Thelayers were separated; the organic layer was washed with diluted NaHCO₃(1.0 L) and then concentrated to ˜350 mL by rotary evaporation at 28° C.and stirred at room temperature for 30 min. Heptane (700 mL) was addedand the resulting slurry was stirred at room temperature for 30 min,cooled to 4° C. and stirred for 1 h. The solids were filtered, washedwith heptane, and then dried under vacuum to yield the title compound(193.0 g, >97% purity). The filtrate was concentrated, slurried in anisopropyl acetate and heptane mixture (1:3, 60 mL) over 30 min, filteredand dried to yield additional product (45.0 g, >97% purity).

c.trans-(7-Cyano-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester

Trifluoro-methanesulfonic acid7-tert-butoxycarbonylamino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-ylester (236.6 g, 0.49 mol) was dissolved in N,N-dimethylformamide (851mL, 10.99 mol) and water (23.8 mL, 1.32 mol) at room temperature. Thesolution was purged with nitrogen for 5 min, and then connected to housevacuum for 5 min. Nitrogen purging and exposure to vacuum was repeatedtwice. To the reaction mixture was added zinc cyanide (34.2 g, 0.29mol), tris(dibenzylideneacetone)dipalladium(0) (4.4 g, 4.8 mmol) and1,1′-bis(diphenylphosphino)ferrocene (5.4 g, 9.7 mmol) with stirring.The reaction mixture was purged with nitrogen for 5 min, heated undernitrogen at 110° C. for 1 h, cooled to room temperature and thenfiltered through celite. The filtered reaction mixture was added slowlyto water (3 L), cooled to 0° C. with stirring, stirred for 30 min at 0°C., and then filtered. The filter cake was washed with water (500 mL)and dried in air for 2 h, slurried in ethanol (1 L) with stirring over 1h, and then filtered to give the title compound (165.0 g, >96% purity).The filtrate was dried (21.6 g) and dissolved in ethanol (110 mL) withstirring over 1 h, and the resulting slurry was filtered and dried undervacuum to give additional product (10.2 g, >98% purity).

Preparation 3:trans-(7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester

A slurry of the product of Preparation 2 (160.0 g, 446.3 mmol) andmethanol (3.3 L) was heated at 55° C. for 15 min, sodium perboratemonohydrate (280 g, 2800 mmol) and water (330 mL) was added and thereaction mixture was heated at 55° C. overnight. Additional sodiumperborate monohydrate (90 g) was added and the reaction mixture washeated at 55° C. overnight, then cooled to room temperature, and theinorganic solids were filtered off. The filtrate was transferred to a 5L flask and most of the solvent was removed by rotary evaporation. Tothe resulting slurry was added water (1.1 L) and ethyl acetate (450 mL)and the reaction mixture was stirred at room temperature for 20 min. Thereaction mixture was filtered and the filter cake was washed with water(200 mL) and then ethyl acetate (200 mL) and dried to yield the titlecompound (123 g, ˜95% purity). The filtrate was concentrated to drynessand dried under vacuum to yield additional product (18 g, 65% purity).

Preparation 4:trans-(7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester

To a mixture oftrans-(7-cyano-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester (33.0 g, 92 mmol), ethanol (45 mL), DMF (25 mL)and water (7.5 mL) was added hydrido(dimethylphosphoniousacid-kP)[hydrogen bis(dimethylphosphinito-kP)]platinum(II) (0.25 g, 0.58 mmol)and the reaction mixture was heated at 80° C. for 24 h. The reaction wascooled to room temperature and concentrated to dryness under vacuum togive the title compound (36.3 g) which was used without furtherpurification. (m/z): [M+H]⁺ calcd for C₂₁H₃₂N₂O₄ 377.24; found 377.8. ¹HNMR (d₆-DMSO, 400 mHz) δ (ppm): 7.92 (s, 1H), 7.64 (m, 2H), 7.26 (s,1H), 7.14 (d, J=7.9 Hz, 1H), 6.64 (d, J=9.4 Hz) 3.81 (t, J=10.0 Hz),3.58 (m, 1H), 3.30 (s, 3H), 2.58 (dd, J=16.9 Hz, 9.4 Hz, 1H), 1.82 (m,1H), 1.56-1.45 (m, 4H), 1.41 (s, 9H), 0.58 (m, 6H).

Preparation 5:trans-(7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester

To a solution oftrans-(7-cyano-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester (8.5 g, 24 mmol) in DMSO (105 mL) was added K₂CO₃(4.98 g, 36 mmol), and the mixture was stirred until all solids weredissolved. To the solution was added 30% hydrogen peroxide (12.2 mL, 120mmol) in 0.5 mL portions over 45 min at a rate to keep the temperature30-35° C. The reaction mixture was diluted with water (200 mL) andisopropyl acetate (500 mL), and sodium metabisulfite was added (10 g) toreduce excess peroxides. Layers were separated and the aqueous layer wasextracted with isopropyl acetate (3×150 mL) and 10% MeOH/isopropylacetate (2×100 mL). The combined organic layers were washed with water(3×150 mL) and saturated NaCl (100 mL), dried with Na₂SO₄ andconcentrated to give the title compound (9.4 g). (m/z): [M+H] calcd forC₂₁H₃₂N₂O₄ 377.24; found 377.6.

Preparation 6:trans-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide

Acetyl chloride (278.8 mL, 3920 mmol) was added dropwise to ethanol (382mL, 6530 mmol) at −5° C. over 2 h keeping the internal temperature below20° C. The resulting solution was added portion wise over 15 min,keeping the internal temperature below 30° C., to a slurry oftrans-(7-carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester (123.0 g, 327 mmol) and ethanol (500 mL) that hadbeen cooled to 10° C. The reaction mixture was stirred at roomtemperature for 2 h, and concentrated to ˜200 mL by rotary evaporation.Ethyl acetate (200 mL) was added and the resulting slurry was stirred at0° C. for 30 min, filtered and dried to yield the hydrochloride salt ofthe title compound (102 g, >98% purity) as a white solid.

Preparation 7: Carbonic acid 4-nitro-phenyl ester (R)-1-phenyl-ethylester

A mixture of (R)-1-phenyl-ethanol (60.6 g, 0.496 mol), pyridine (42.5mL, 0.526 mol) and 2-methyl-tetrahydrofuran (600 mL) was cooled to 0° C.and p-nitrophenyl chloroformate (100 g, 0.496 mol) was added over 15 minkeeping the internal temperature below 5° C. The reaction mixture waswarmed to room temperature and stirred for 2 h. To the reaction mixturewas added 1.0 M HCl in water (300 mL). Layers were separated. Theorganic layer was washed with 1N HCl (300 mL) and brine (300 mL),filtered, concentrated to dryness by rotary evaporation, and dried undervacuum to give the title compound (140 g) as a clear yellow oil.

Preparation 8:(6S,7S)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide a.((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid (R)-1-phenyl-ethyl ester

A mixture of carbonic acid 4-nitro-phenyl ester (R)-1-phenyl-ethyl ester(102 g, 357 mmol), N,N-dimethylformamide (200 mL) and triethylamine(32.7 mL, 235 mmol) was stirred at room temperature overnight. To thereaction mixture was addedtrans-7-amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide hydrochloride (100 g, 320 mmol), N,N-dimethylformamide (320mL) and triethylamine (98.0 mL, 703 mmol). The reaction mixture washeated at 85° C. for 5 h and then stirred at room temperature overnight.Approximately 90% of the DMF was removed by distillation at 70° C. andthe resulting thick oil was cooled to room temperature and thenpartitioned between ethyl acetate (1.5 L) and diluted brine (500 mL).The organic layer was washed with 1M NaOH (3×500 mL) and dried withNa₂SO₄. Most of the solvent was removed by rotary evaporation, 3 volumesethyl acetate were added and resulting slurry was stirred at roomtemperature for 30 min, filtered and dried to give the title compound(48 g, >99% chemical and optical purity).

The filtrate was washed with 1M NaOH (200 mL) and then with dilutedbrine (2×200 mL). Most of the solvent was removed by rotary evaporationyielding a thick oil to which ethyl acetate (100 mL) was added. A pinchof seeds of the title compound was added and the reaction mixture wasrefrigerated at 0° C. after stirring for ˜30 min. The resulting thinslurry was stirred for 5 min and filtered; flask and filter cake werewashed with ethyl acetate (2×15 mL) to yield additional title compound(4.1 g, 97% chemical and >99% optical purity, 38% combined yield).

b.(6S,7S)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide

Acetyl chloride (193 mL, 2710 mmol) was added dropwise to ethanol (260mL, 4500 mmol) at −5° C. over 40 min keeping the internal temperaturebelow 30° C. The resulting solution was added over 5 min, at 10° C., toa mixture of((2S,3S)-7-carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid (R)-1-phenyl-ethyl ester (49.0 g, 115 mmol) and ethanol (200 mL).The reaction mixture was stirred at room temperature overnight, andconcentrated to ˜100 mL by rotary evaporation. Ethyl acetate (100 mL)was added and the resulting slurry was stirred at 0° C. for 30 min andfiltered. The filter cake was washed with ethyl acetate and dried toyield the hydrochloride salt of the title compound (30 g, >99% purity).The volume of the filtrate was reduced almost to dryness. Isopropylalcohol (20 mL) was added and the resulting thick slurry was stirred for30 min and filtered. The filter cake was washed with ethyl acetate (2×20mL) and dried under vacuum overnight to yield additional product (5.5g, >97% purity). ¹H NMR (DMSO-d₆): δ (ppm) 0.49 (t, 3H), 0.63 (t, 3H),1.62 (q, 2H), 1.89 (m, 1H), 2.09 (m, 1H), 2.60 (dd, 1H), 3.22 (m, 1H),3.41 (s, 3H), 3.50 (dd, 1H), 3.82 (q, 1H), 7.19 (d, 1H), 7.31 (br, 1H),7.70 (d, 1H), 7.71 (s, 1H), 7.98 (br, 1H), 8.15 (br, 3H).

Preparation 9:trans-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-ol

To a solution oftrans-(1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester (6.0 g, 17.2 mmol) in dichloromethane (60 mL) wasadded a solution of 4.0 N HCl in dioxane (21.5 mL, 86 mmol) overapproximately 2 min. After stirring at room temperature overnight, thereaction mixture was concentrated at reduced pressure and dried undervacuum to give the hydrochloride salt of the title compound (5.5 g)(m/z): [M+H]⁺ calcd for C₁₅H₂₃NO₂ 250.36; found 250.2. ¹H NMR (d₆-DMSO,400 mHz) δ (ppm) 9.26 (s, 1H), 8.09 (br s, 3H), 6.92 (d, J=8.0 Hz, 1H),6.61 (m, 2H), 3.77 (m, 1H), 3.41 (s, 3H), 3.30 (dd, J=15.8 Hz, 5.9 Hz,1H), 3.17 (m, 1H), 2.43 (dd, J=15.5 Hz, 9.6 Hz, 1H), 1.85 (m, 2H),1.66-1.50 (m, 2H), 0.66 (t, J=7.4 Hz, 3H), 0.54 (t, J=7.1 Hz, 3H).

Preparation 10:(6S,7S)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-oland(6R,7R)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-ola.((2R,3R)-1,1-Diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid (R)-1-phenyl-ethyl ester (RR) and((2S,3S)-1,1-Diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid (R)-1-phenyl-ethyl ester (SS)

A mixture oftrans-7-amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-01hydrochloride salt (1.00 g, 3.5 mmol), carbonic acid 4-nitro-phenylester (R)-1-phenyl-ethyl ester (800 mg, 2.8 mmol), triethylamine (707mg, 7.0 mmol) and DMF (3.5 mL) was heated at 90° C. After 4 h, anadditional portion of carbonic acid 4-nitro-phenyl ester(R)-1-phenyl-ethyl ester (200 mg, 0.7 mmol) was added, and heatingcontinued for another 3 h. The reaction mixture was cooled and allowedto stand at room temperature overnight. The DMF was removed at reducedpressure and the residue was dissolved in ethyl acetate (25 mL). Theorganics were washed with 10% sodium carbonate and saturated sodiumchloride, dried with Na₂SO₄ and concentrated to dryness. The residue wasdissolved in methanol (6 mL) and a 1.0 N solution of sodium hydroxide inmethanol (3.0 mL, 3.0 mmol) was added. The reaction mixture was stirredat room temperature for 30 min, at which time 50% aqueous acetic acid (2mL) was added. The reaction mixture was concentrated to approximately 4mL, and 50% aqueous acetonitrile (15 mL) was added.

The crude diastereomers were separated by preparative HPLC and collectedseparately. Crude product was dissolved in 1:1 acetonitrile/water andseparated under the following conditions: column: Microsorb C18 100 A 8μm column; flow rate: 50 mL/min; Solvent A: >99% water, 0.05 TFA;Solvent B: >99% acetonitrile, 0.05 TFA; Gradient (time(min)/% B): 0/15,4/15, 8/40, 60/55. The pure fractions of each were pooled and theacetonitrile was removed at reduced pressure. The product was extractedinto dichloromethane (3×30 mL), the organic extracts were dried withNa₂SO₄ and concentrated to give the title compounds.

RR: 435 mg (39% yield) (m/z): [M+H]⁺ calcd for C₂₄H₃₁NO₄ 398.52; found398.2. ¹H NMR (d₆-DMSO, 400 mHz) δ (ppm) 9.01 (s, 1H), 7.37-7.26 (m,5H), 7.05 (d, J=9.8 Hz, 1H), 6.86 (d, 8.2, 1H), 6.52 (dd, J=8.0, 2.4 Hz,1H), 6.48 (d, J=2.3 Hz, 1H), 5.70 (guar, J=6.7 Hz, 1H), 3.77 (t, J=10.3Hz, 1H), 3.55 (m, 1H), 3.32 (s, 3H), 3.17 (dd, J=15.9, 6.0 Hz, 1H), 2.43(m, 1H), 1.57-1.52 (m, 2H), 1.56 (d, J=6.7 Hz, 3H), 1.44-1.33 (m, 2H),0.60 (t, J=7.4 Hz, 3H), 0.51 (t, J=7.0 Hz, 3H).

SS: 363 mg (32% yield) (m/z): [M+H]⁺ calcd for C₂₄H₃₁NO₄ 398.52; found398.2. ¹H NMR (d₆-DMSO, 400 mHz) δ (ppm) 9.02 (s, 1H), 7.39-7.24 (m,5H), 7.03 (d, J=9.7 Hz, 1H), 6.85 (d, 8.3, 1H), 6.53 (dd, J=8.1, 2.6 Hz,1H), 6.48 (d, J=2.2 Hz, 1H), 5.69 (guar, J=6.7 Hz, 1H), 3.75 (t, J=10.6Hz, 1H), 3.52 (m, 1H), 3.27 (s, 3H), 3.14 (dd, J=15.9, 5.9 Hz, 1H), 2.37(dd, J=15.7, 9.5, 1H), 1.65-1.41 (m, 4H), 1.46 (d, J=6.6 Hz, 3H),0.64-0.60 m, 6H).

b.(6S,7S)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-ol

((2S,3S)-1,1-Diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid (R)-1-phenyl-ethyl ester (635 mg, 1.60 mmol) was treated with 4.0 NHCl in dioxane (6.0 mL, 24 mmol) and stirred at RT. After 3 days, thesolvent was removed at reduced pressure and the residual solid wastriturated with 50% dichloromethane in heptane (4 mL). The solid wascollected on a Buchner funnel and dried under vacuum to give thehydrochloride salt of the title compound (462 mg). (m/z): [M+H]⁺ calcdfor C₁₅H₂₃NO₂ 250.36; found 250.2. ¹H NMR (d₆-DMSO, 400 mHz) δ (ppm)9.23 (s, 1H), 8.02 (br s, 3H), 6.92 (d, J=8.2 Hz, 1H), 6.61 (m, 2H),3.77 (m, 1H), 3.41 (s, 3H), 3.30 (m, 1H), 3.17 (m, 1H), 2.44 (dd, J=15.9Hz, 9.8 Hz, 1H), 1.85 (m, 2H), 1.62-1.52 (m, 2H), 0.66 (t, J=7.2 Hz,3H), 0.55 (t, J=7.0 Hz, 3H).

c.(6R,7R)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-ol

Following the procedure of the previous step using((2R,3R)-1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid (R)-1-phenyl-ethyl ester, the hydrochloride salt of the titlecompound was prepared. (m/z): [M+H]⁺ calcd for C₁₅H₂₃NO₂ 250.36; found250.4. ¹H NMR (d₆-DMSO, 400 mHz) δ (ppm) 9.23 (s, 1H), 8.02 (br s, 3H),6.92 (d, J=8.2 Hz, 1H), 6.61 (m, 2H), 3.77 (m, 1H), 3.41 (s, 3H), 3.30(m, 1H), 3.17 (m, 1H), 2.44 (dd, J=15.7 Hz, 10.2 Hz, 1H), 1.84 (m, 2H),1.62-1.52 (m, 2H), 0.66 (t, J=7.4 Hz, 3H), 0.55 (t, J=7.0 Hz, 3H).

Preparation 11:((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid (R)-1-phenyl-ethyl ester (SS) and((2R,3R)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid (R)-1-phenyl-ethyl ester (RR)

A mixture of carbonic acid 4-nitro-phenyl ester (R)-1-phenyl-ethyl ester(7.35 g, 25.6 mol),trans-7-amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide hydrochloride (4.0 g, 13 mmol) and triethylamine (5.3 mL, 38mol) in DMF (13 mL) was heated at 85° C. After 2.5 hours, the reactionmixture was cooled and stirred at room temperature overnight. Solventwas removed under vacuum and the residue was purified by silica gelchromatography eluting with EtOAc in DCM (10% to 50% gradient) to give amixture containing the title compounds (6.96 g). The mixture ofdiastereomers was separated by preparative HPLC under the conditionsdescribed in Preparation 10 (a) except for use of the following gradient(time(min)/% B): 0/5, 4/5, 8/37, 60/42. The pure fractions of eachisomer were pooled and lyophylized to give the title compounds.

SS: 1.4 g (26%) (m/z): [M+H]⁺ calcd for C₂₅H₃₂N₂O₄ 425.24; found 425.6.

RR: 1.5 g (28%) (m/z): [M+H]⁺ calcd for C₂₅H₃₂N₂O₄ 425.24; found 425.4.

Single Crystal X-Ray Diffraction Analysis of Diastereomer SS

SS (3 mg) was dissolved in acetonitrile (100 mL) in an open HPLC vial,which was partially immersed in a 20 mL vial containing 1:9acetonitrile:water (4 mL). The 20 mL vial was capped and held at roomtemperature to provide large birefringent needle shaped crystals of SS.

X-ray diffraction crystal structure data was obtained for a singlecrystal with dimensions 0.44×0.13×0.10 mm using Mo K_(α) radiation(λ=0.71073 Å) on a Nonius KappaCCD diffractometer equipped with agraphite crystal and incident beam monochromator, and analyzed on aLINUX PC using SHELX97 software. The following lattice parameters werederived: unit cell is hexagonal with dimensions a=17.451 Å, b=17.451 Å,c=19.822 Å, α=90.00°, β=90.00°, γ=120.00°, cell volume (V)=5228 Å³,space group is P 3_(I)21. The molecule contains three chiral centers.From the known R configuration of the carbon bearing the phenyl group:

the remaining two centers were determined to be in the S configuration.

Remaining crystals were analyzed by powder x-ray diffraction. Powderx-ray diffraction peaks predicted from the derived single crystalcrystallographic data were in good agreement with observed powder x-raydiffraction peaks.

Preparation 12:(6R,7R)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide

((2R,3R)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid (R)-1-phenyl-ethyl ester (1.7 g, 4.0 mmol) was treated with 4.0 NHCl in dioxane (20 mL, 80 mmol) and stirred at RT. After 24 h, thesolvent was removed at reduced pressure and the residual solid wastriturated with 50% dichloromethane in hexane (15 mL). The solid wascollected on a Buchner funnel, rinsed with 50% dichloromethane in hexane(10 mL) and dried under vacuum to give the title compound as thehydrochloride salt (1.2 g). (m/z): [M+H]⁺ calcd for C₁₆H₂₄N₂O₂ 277.19;found 277.4. ¹H NMR (d₆-DMSO, 400 mHz) δ (ppm) 8.19 (br s, 3H), 7.98 (s,1H), 7.70 (m, 2H), 7.32 (s, 1H) 7.19 (d, J=7.8 Hz, 1H), 3.83 (m, 1H),3.47 (m, 1H), 3.42 (s, 3H), 3.23 (m, 1H), 2.63 (dd, J=16.8 Hz, 9.7 Hz,1H) 2.06 (m, 1H), 1.88 (m, 1H) 1.64 (guar, J=7.7 Hz, 2H), 0.62 (t, J=7.5Hz, 3H), 0.50 (t, J=7.0 Hz, 3H).

Preparation 13: Sodium(S)-4-cyclohexyl-1-hydroxy-3-methoxycarbonyl-butane-1-sulfonate a:(S)-2-Cyclohexylmethyl-4-hydroxy-butyric acid methyl ester

A mixture of (S)-2-cyclohexylmethyl-succinic acid 1-methyl ester (60.0g, 263 mmol) and tetrahydrofuran (600 mL) was stirred at roomtemperature and then cooled to −5° C. over 30 min. To the reactionmixture was added 1.0 M borane in tetrahydrofuran (520 mL) dropwise over45 min, keeping the internal temperature below 0° C. To the reactionmixture was added MeOH (100 mL) dropwise to quench the reaction. Thereaction mixture was concentrated to about 100 mL by rotary evaporation.(Trifluoromethyl)benzene (200 mL) was added and volume was reduced to 25mL by rotary evaporation. (Trifluoromethyl)benzene (100 mL) was added tothe resulting thick oil and the volume was reduced to ˜25 mL to providecrude title product (56.3 g).

b. Sodium(S)-4-cyclohexyl-1-hydroxy-3-methoxycarbonyl-butane-1-sulfonate

A mixture of (S)-2-cyclohexylmethyl-4-hydroxy-butyric acid methyl ester(44.8 g, 209 mmol) and DCM (310 mL) was cooled to 5° C. with stirring.To the reaction mixture was added a solution of potassium bromide (2.5g, 21 mmol) and sodium bicarbonate (2.4 g, 29 mmol) in distilled water(130 mL), and then 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) (0.33 g,2.1 mmol), followed by the addition of sodium hypochlorite (140 mL, 210mmol) at the rate of 130 mL/h keeping the internal temperature in therange of 6-8° C. The reaction mixture was stirred for 15 min and DCM(200 mL) was added. Layers were separated and the organic layer waswashed with saturated brine (200 mL), and dried with Na₂SO₄.

To the organic layer was added EtOAc (40 mL) followed by the addition ofsodium bisulfite (21.8 g, 209 mmol). The reaction solution wasconcentrated to remove half of the DCM (˜175 mL) by rotary evaporation.Water (2 mL) were added to the reaction solution which was stirred atroom temperature overnight. The resulting slurry was filtered; thefilter cake was dried under vacuum overnight to yield the title compound(61.9 g). ¹H NMR (DMSO-d₆): δ (ppm) 0.78 (m, 2H), 0.95-1.20 (m, 4H),1.33 (m, 1H), 1.40-1.95 (m, 5H), 2.45-2.65 (m, 1H), 3.21 (m, 2H), 3.45(s, 3H), 3.6-3.8 (m, 1H), 5.18 (d, 1H).

Preparation 14:trans-7-Amino-8,8-dimethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide a. 7-Methoxy-1,1-dimethyl-3,4-dihydro-1H-napthalen-2-one

A slurry of sodium tent butoxide (21.1 g, 220 mmol) in THF (100 mL) wascooled to 0° C. A solution of 7-methoxy-3,4-dihydro-1H-napthalen-2-one(17.6 g, 100 mmol) and methyl iodide (30.1 g, 220 mmol) in THF (100 mL)was added dropwise over 40 min, and the reaction mixture was warmed toroom temperature after 10 min. Water (200 mL) and EtOAc (600 mL) wasadded. The layers were separated, the organic layer was washed withwater (5×100 mL) and saturated NaCl (100 mL), filtered and dried withNa₂SO₄ to provide the title compound (20 g).

b. 7-Methoxy-1,1-dimethyl-3,4-dihydro-1H-napthalen-2-one oxime

To a solution of 7-methoxy-1,1-dimethyl-3,4-dihydro-1H-napthalen-2-one(25.4 g, 98 mmol) in methanol (175 mL) was added a solution ofhydroxylamine hydrochloride (20.5 g, 295 mmol) and sodium acetate (24.2g, 295 mmol) in water (175 mL) and the reaction mixture was heated at70° C. for 3 h, and cooled in ice over 30 min. The solid was collectedon a Buchner funnel, stirred with methanol (125 mL) at 50° C. for 30min, and then stirred at RT overnight. The reaction mixture was cooledto 0° C.; solid was collected on a Buchner funnel, rinsed with coldmethanol (20 mL) and dried under vacuum to give the title compound (14.7g).

c.(1aS,7aR)-4-Methoxy-2,2-dimethyl-1a,2,7,7a-tetrahydro-1H-1-aza-cyclopropa[b]-naphthalene

To a solution of 7-methoxy-1,1-dimethyl-3,4-dihydro-1H-napthalen-2-oneoxime (15.3 g, 70 mmol) in THF (240 mL) was added diethylamine (18 mL).The reaction mixture was cooled to 0° C. and a 2.0 M solution of lithiumaluminum hydride in THF (100 mL, 200 mmol) was added slowly over 20 minto control the rate of hydrogen evolution. The reaction mixture washeated to 70° C. for 1 h, cooled to 0° C. and Na₂SO₄ 10H₂O (20 g), brine(60 mL), and EtOAc (300 mL) were added. The solid were washed with EtOAc(4×100 mL); the combined organic layers were washed with water (4×100mL) and brine (100 mL), dried with Na₂SO₄, and concentrated to givecrude title product (14.3 g). The crude product was dissolved in EtOAc(500 mL), extracted with 0.1 N HCl (100 mL), then with 0.3 N HCl (225mL). Sodium carbonate (8 g, 75 mmol) was added to the aqueous layerwhich was extracted with EtOAc (4×200 mL). Organic layers were combined,dried with Na₂SO₄ and concentrated to give the title compound as an oil(10.1 g) which crystallized on standing to a tan solid. (m/z): [M+H]calcd for C₁₁H₁₇NO 204.14; found 204.2.

d.trans-(7-Hydroxy-3-methoxy-1,1-dimethyl-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester

Using a procedure similar to that of Preparations 1(b) and 2(a), thetitle compound was prepared. ¹H NMR (d₆-DMSO, 400 mHz) δ (ppm): 9.04 (s,1H), 6.83 (d, J=8.2 Hz, 1H), 6.69 (d, J=9.4 Hz, 1H), 6.65 (d, J=2.5 Hz,1H), 6.52 (dd, J=8.2, 2.5 Hz, 1H), 3.50 (m, 1H), 3.45 (m, 1H), 3.30 (s,3H), 3.15 (m, 1H), 2.55 (m, 1H), 1.34 (s, 9H), 1.16 (s, 3H), 1.00 (s,3H).

e.trans-(7-Carbamoyl-3-methoxy-1,1-dimethyl-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester

Using a procedure similar to that of Preparations 2(b), 2(c), and 5, thetitle compound was prepared. (m/z): [M+H]⁺ calcd for C₁₉H₂₈N₂O₄ 349.21;found 349.1.

f.trans-(7-Amino-6-methoxy-8,8-dimethyl-5,6,7,8-tetrahydronaphthalene-2-carboxylicacid amide

To a slurry oftrans-(7-carbamoyl-3-methoxy-1,1-dimethyl-1,2,3,4-tetrahydro-naphthalen-2-yl)-carbamicacid tert-butyl ester (9.22 g, 26.4 mmol) in DCM (100 mL) was added 4 NHCl in dioxane (25 mL, 100 mmol) slowly. The reaction mixture wasstirred at RT for 15 h, concentrated to dryness, triturated with DCM (25mL) for 30 min, filtered, rinsed with DCM (3×15 mL), and dried undervacuum. Ethanol (100 mL) was added and the reaction mixture wasconcentrated under vacuum to give the HCl salt of the title compound(7.17 g) as a white powder. (m/z): [M+H] calcd for C₁₄H₂₀N₂O₂ 249.16;found 249.1. ¹H NMR (d₆-DMSO, 400 mHz) δ (ppm): 8.18 (s, 3H), 8.00 (s,1H), 7.92 (d, J=1.6 Hz, 1H), 7.66 (dd, J=8.0 Hz, 1.8 Hz, 1H), 7.32 (s,1H), 7.17 (d, J=8.0 Hz, 1H), 3.70 (m, 1H), 3.44 (s, 3H), 3.43 (m, 1H),3.22 (m, 1H), 2.67 (dd, J=16.4 Hz, 10.2 Hz), 1.50 (s, 3H), 1.24 (s, 3H).

Preparation 15: (S)-2-Cyclohexylmethyl-4-oxo-butyric acid methyl estera. (S)-2-Cyclohexylmethyl-4-hydroxy-butyric acid methyl ester

A mixture of (S)-2-cyclohexylmethyl-succinic acid 1-methyl ester (484mg, 2.12 mmol) and tetrahydrofuran 10 mL) was stirred at roomtemperature and then cooled to 0° C. To the reaction mixture was added1.0 M borane in tetrahydrofuran (4.2 mL) dropwise over 5 min. After 2 h,MeOH was added drop-wise to quench the reaction. The reaction mixturewas stirred for 30 min at room temperature and then concentrated todryness. The crude residue was suspended in MeOH, concentrated todryness, and purified on SiO₂ (40 g) using 5-10% MeOH/DCM as eluent toprovide the title compound (0.32 g) as a clear oil: ¹H NMR (CDCl₃, 400mHz) δ (ppm): 3.69-3.65 (m, 5H), 2.65 (m, 1H), 1.85-1.59 (m, 8H),1.32-1.12 (m, 5H), 0.87 (m, 2H).

b. (S)-2-Cyclohexylmethyl-4-oxo-butyric acid methyl ester

A mixture of the product of the previous step (0.32 g, 1.49 mmol),N,N-diisopropylethylamine (0.65 mL, 3.7 mmol), dimethyl sulfoxide (0.26mL, 3.7 mmol), and dichloromethane (20 mL, 0.3 mol) was cooled to 0° C.and flushed with nitrogen. Sulfur trioxide-pyridine complex (0.59 g, 3.7mmol) was added under a stream of nitrogen and the reaction mixture wasstirred for 1.5 h. To the reaction mixture was added 0.1 N HCl. Theorganic layer was washed with 0.1N HCl (2×) and brine (2×), dried withNa₂SO₄, filtered, and concentrated to dryness to provide the titlecompound (0.305 g) as a clear oil which was used without furtherpurification. ¹H NMR (CDCl₃, 400 mHz) δ (ppm): 9.75 (s, 1H), 3.69 (s,3H), 3.02-2.96 (m, 1H), 2.84 (dd, J=18.0, 9.0 Hz, 1H), 2.55 (dd, J=18,4.7 Hz, 1H), 1.79-1.12 (m, 11H), 0.93-0.84 (m, 2H).

Preparation 16: Aldehyde Reagents

Following the process of Preparation 14 using the appropriate methylester in place of (S)-2-cyclohexylmethyl-succinic acid 1-methyl ester,the following aldehydes were prepared:

(R)-2-Cyclohexylmethyl-4-oxo-butyric acid methyl ester: ¹H NMR (CDCl₃,400 mHz) δ (ppm): 9.76 (s, 1H), 3.69 (s, 3H), 3.01-2.96 (m, 1H), 2.84(dd, J=18.0, 9.0 Hz, 1H), 2.55 (dd, J=18, 4.7 Hz, 1H), 1.79-1.14 (m,11H), 0.92-0.96 (m, 2H).

(S)-2-Cyclohexyl-4-oxo-butyric acid methyl ester: ¹H NMR (CDCl₃, 400mHz) δ(ppm): 9.78 (s, 1H), 3.69 (s, 3H), 2.91 (dd, J=18, 10 Hz, 1H),2.80-2.75 (m, 1H), 2.56 (dd, J=18, 3.5 Hz, 1H), 1.84-0.98 (m, 11H).

(S)-2-pentyl-4-oxo-butyric acid methyl ester: ¹H NMR (CDCl₃, 400 mHz)δ(ppm): 9.76 (s, 1H), 3.70 (s, 3H), 2.92-2.84 (m, 2H), 2.80-2.75 (m,1H), 2.58-2.54 (m, 1H), 1.67-1.63 (m, 1H), 1.57-1.48 (m, 2H), 1.28 (bs,6H), 0.89-0.86 (m, 3H).

(S)-2-Phenylpropyl-4-oxo-butyric acid methyl ester: ¹H NMR (CDCl₃, 400mHz): confirmed the presence of aldehyde with a peak at 9.75 (s, 1H).

(S)-2-Isobutyl-4-oxo-butyric acid methyl ester: ¹H NMR (CDCl₃, 400 mHz)δ(ppm): 9.76 (s, 1H), 3.70 (s, 3H), 3.1-2.94 (m, 1H), 2.88-2.81 (m, 1H),2.62-2.52 (m, 1H), 1.66-1.26 (m, 3H), 0.97-0.88 (m, 6H).

(R)-2-Isobutyl-4-oxo-butyric acid methyl ester: ¹H NMR (CDCl₃, 400 mHz)δ(ppm): 9.76 (s, 1H), 3.70 (s, 3H), 2.96-2.93 (m, 1H), 2.84 (dd, J=18,9.0 Hz, 1H), 2.55 (dd, J=18, 4.5 Hz, 1H), 1.64-1.25 (m, 3H), 0.94-0.86(m, 6H).

(S)-2-Isopropyl-4-oxo-butyric acid methyl ester. ¹H NMR (CDCl₃, 400mHz): confirmed the presence of aldehyde with a peak at 9.79 (s, 1H).

(S)-4,4-Dimethyl-2-(2-oxo-ethyl)-pentanoic acid methyl ester: ¹H NMR(CDCl₃, 400 mHz) δ (ppm): 9.73 (s, 1H), 3.69 (s, 3H), 2.80 (dd, J=17.8,8.0 Hz, 1H), 2.57 (dd, J=18, 5.8 Hz, 1H), 1.79 (dd, J=14, 8.41 Hz, 1H),1.50-1.40 (m, 1H), 1.25 (dd, J=14, 3.7 Hz, 1H), 0.91 (s, 9H).

(R)-4,4-Dimethyl-2-(2-oxo-ethyl)-pentanoic acid methyl ester: ¹H NMR(CDCl₃, 400 mHz) δ (ppm): 9.73 (s, 1H), 3.69 (s, 3H), 2.80 (dd, J=17.8,8.0 Hz, 1H), 2.57 (dd, J=17.8, 5.67 Hz, 1H), 1.79 (dd, J=14.1, 8.41 Hz,1H), 1.50-1.41 (m, 1H), 1.25 (dd, J=14.1, 3.7 Hz, 1H), 0.91 (s, 9H).

(S)-Benzyl-4-oxo-butyric acid methyl ester: ¹H NMR (CDCl₃, 400 mHz) δ(ppm): confirmed the presence of aldehyde with a peak at 9.70 (s, 1H)

(R)-2-Butyl-4-oxo-butyric acid methyl ester: ¹H NMR (CDCl₃, 400 mHz) δ(ppm): 9.76 (s, 1H), 3.69 (s, 3H), 2.91-2.87 (m, 1H), 2.57-2.54 (m, 1H),1.70-1.25 (m, 6H), 0.92-0.87 (m, 3H)

Preparation 17: Sodium(S)-3-benzyloxycarbonyl-4-cyclohexyl-1-hydroxy-butane-1-sulfonate a.(S)-2-cyclohexylmethyl-4,4-dimethoxy-butyric acid methyl ester

To a slurry of sodium(S)-4-cyclohexyl-1-hydroxy-3-methoxycarbonyl-butane-1-sulfonate (400.0g, 1.26 mol) and methanol (2 L) was added 4.0 M HCl in 1,4-dioxane (400mL) and the reaction mixture was stirred for 15 min. Trimethoxymethane(340 mL, 3.11 mol) was added and reaction mixture was heated at 50° C.overnight, and then cooled to room temperature. White solids werefiltered off and discarded. Most of the solvent was removed from thefiltrate by rotary evaporation. Ethyl acetate (800 mL) was addedresulting in more precipitation. The white precipitate was removed byfiltration. Solvent was removed from the filtrate by rotary evaporationand then under high vacuum at room temperature overnight to yield thetitle compound (211 g) as a thick oil. ¹H NMR (400 MHz, DMSO-d₆): δ(ppm) 4.25 (t, 1H), 3.57 (s, 3H), 3.18 (s, 6H), 2.43 (m, 1H), 1.55-1.81(m, 2H), 1.50-1.72 (m, 5H), 1.20-1.48 (m, 2H), 1.05-1.21 (m, 4H),0.71-0.92 (m, 2H).

b. Potassium (S)-2-cyclohexylmethyl-4,4-dimethoxy-butyrate

Potassium hydroxide (289.6 g, 2322 mmol) was added to a solution of theproduct of the previous step (200.0 g, 0.77 mol) in methanol (700 mL) inone portion and the reaction mixture was stirred at RT for 20 h.Hydrogen chloride (130 mL, 1.5 mol) was added slowly until the reactionmixture had a pH ˜8 (color change from greenish to orange) resulting inprecipitation of fine solids. Solids were removed by filtration. Solventwas removed from the filtrate. Acetonitrile (1 L) was added to the crudeproduct and the resulting slurry was stirred at room temperatureovernight. The thick slurry was filtered, the filter cake was washedwith acetonitrile (50 mL) and dried to yield a first crop of the titlecompound (133 g) as an off-white solid. Solvent was removed from thefiltrate which was then dried under vacuum to yield about 100 g of apasty solid. MTBE (500 mL) was added and the solids were stirred at RTovernight resulting in a thick slurry which was filtered and dried underhigh vacuum to yield a second crop of the title compound (82 g). ¹H NMR(400 MHz, DMSO-d₆): δ (ppm) 4.28 (dd, 1H), 3.12 (s, 3H), 3.15 (s, 3H),1.95 (m, 1H), 1.75 (m, 1H), 1.51-1.65 (m, 6H), 1.22-1.39 (m, 2H),1.05-1.20 (m, 4H), 0.85-0.93 (m, 1H), 0.65-0.81 (m, 2H).

c: (S)-2-Cyclohexylmethyl-4,4-dimethoxy-butyric acid benzyl ester

Benzyl bromide (50.54 mL, 424.9 mmol) was added to a slurry of theproduct of the previous step (150.0 g, 531.1 mmol) in acetonitrile (2.0L) in one portion and the heterogeneous reaction mixture was stirred atroom temperature overnight. Additional benzyl bromide (5.05 mL, 42.49mmol) was added and the reaction mixture was stirred at room temperaturefor 18 h. Solids were removed by filtration. The filtrate was dried byrotary evaporation and then under high vacuum overnight yielding thetitle compound (162 g). ¹H NMR (400 MHz, DMSO-d₆): δ 7.22-7.40 (m, 5H),5.0-5.15 (q, 2H), 4.23 (t, 1H), 3.15 (s, 3H), 3.17 (s, 3H), 2.52 (m,1H), 1.78 (m, 1H), 1.69 (m, 1H), 1.45-1.61 (m, 6H), 1.20-1.43 (m, 2H),1.0-1.15 (m, 4H), 0.70-0.83 (m, 2H).

d. Sodium(S)-3-benzyloxycarbonyl-4-cyclohexyl-1-hydroxy-butane-1-sulfonate

To a mixture of the product of the previous step (160.0 g, 478.4 mmol)and acetonitrile (1.0 L) was added 1.0 M HCl in water (1.2 L) and thereaction mixture was heated at 35-40° C. for 2 h. Ethyl acetate (1.2 L)was added, phases were separated, and the organic layer was washed withbrine (1 L). Sodium bisulfite (74.7 g, 718 mmol) was added to the wetorganic layer and the reaction mixture was stirred at RT overnight. Mostof the solvent was removed by rotary evaporation and acetonitrile (1 L)was added and the resulting slurry was stirred at RT overnight. Theresulting thick white slurry was filtered, the filter cake was washedwith acetonitrile (2×100 mL) and dried under vacuum to yield the titlecompound (200 g, >98% purity) as a white solid. ¹H NMR (400 MHz,DMSO-d₆): δ 7.23-7.41 (m, 5H), 5.30 (d, 1H), 4.98-5.18 (q, 2H),3.75-3.88 (m, 1H), 3.60-3.79 (m, 1H), 2.05 (m, 0.5H), 1.45-1.82 (m,2.5H), 1.45-1.60 (m, 5H), 1.20-1.42 (m, 2H), 1.0-1.17 (m, 4H), 0.69-0.82(m, 2H).

Example 1(S)-4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid a.(S)-4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid methyl ester

To a slurry of sodium(S)-4-cyclohexyl-1-hydroxy-3-methoxycarbonyl-butane-1-sulfonate (25.8 g,81.5 mmol) and 2-methyl-tetrahydro-furan (300 mL) was added 1.0 M NaOHin water (76.1 mL) and the reaction mixture was stirred for 20 min atRT. To the reaction mixture was added(6S,7S)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide hydrochloride (17.0 g, 54.3 mmol); the reaction mixture wasstirred for 40 min at RT, sodium triacetoxyborohydride (46.1 g, 217mmol) was added in 4 portions. The reaction mixture was stirred at RTovernight after the first two portions. Water (200 mL) and MeTHF (100mL) were added; the phases were separated and the organic layer waswashed with 1 M NaOH (2×200 mL), diluted brine (200 mL) dried withNa₂SO₄ and solvent was removed to yield crude title intermediate (22 g)as a glassy yellow solid.

Crude product was purified by reverse-phase chromatography using aMicrosorb 100-10 BDS 4 inch column. Crude product was dissolved in 1:1acetonitrile: 1 M aq. HCl (150 mL) solvent mixture and eluted with water(0.1% HCl)/acetonitrile mobile phase (10-40% gradient). Pure fractions(>98%) were combined, most of the acetonitrile was removed by rotaryevaporation, pH was adjusted to pH ˜12 with solid Na₂CO₃ and purifiedproduct was extracted with MeTHF (3×1 L). Combined organic layers weredried with Na₂SO₄ and solvent removed to yield the title compound (16.5g)

b.(S)-4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid

To a solution of(S)-4-((2S,3S)-7-carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid methyl ester (12.0 g, 25.4 mmol) in methanol was added 5.0 M NaOH(25 mL) and the reaction mixture was heated at 30° C. for 8 h and thenat 25° C. overnight. Most of the methanol solvent was removed by rotaryevaporation at 25° C., water (100 mL) and isopropyl acetate (100 mL) wasadded and the resulting mixture was stirred for 15 min. The bottom twoof three layers were extracted with isopropyl acetate (100 mL). Bottomlayers were cooled to −5° C. and MeTHF (200 mL) was added and thenconcentrated HCl (˜15 mL) was added in portions until pH ˜2. Phases wereseparated, water layer was washed with MeTHF (100 mL) and combinedorganic layers were dried with Na₂SO₄. Most of the organic solvent wasremoved by rotary evaporation, ethyl acetate (200 mL) was added and thevolume was reduced to 50 mL. Ethyl acetate (200 mL) was added and theresulting slurry was stirred/triturated at RT for 3 h. Product wasfiltered under nitrogen and dried under vacuum for 48 h to yield thehydrochloride salt of the title compound (11 g, 98.2% purity) as a whitesolid. ¹H NMR (DMSO-d₆): 6(ppm) 0.54 (t, 3H), 0.63 (t, 3H), 0.82 (m,2H), 1.05-1.3 (m, 6H), 1.45 (m, 1H), 1.55-2.0 (m, 10H), 2.40 (m, 1H),2.67 (dd, 1H), 3.06 (m, 1H), 3.22 (m, 1H), 3.30 (dd, 1H), 3.41 (s, 3H),3.45 (dd, 1H), 4.05 (m, 1H), 7.19 (d, 1H), 7.50 (br, 1H), 7.69 (d, 1h),7.70 (s, 1H), 7.95 (br, 2H), 9.26 (br, 1H).

Example 2(S)-4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid methyl ester

(S)-2-cyclohexylmethyl-4-oxo-butyric acid methyl ester (822 mg, 3.38mmol),(6S,7S)-7-amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydronaphthalene-2-carboxylicacid amide hydrochloride (1.01 g, 3.23 mmol) and triethylamine (326 mg,3.23 mmol) were dissolved in dichloromethane (15 mL) and methanol (10mL). Sodium triacetoxyborohydride (1.03 g, 4.85 mmol) was added. Over 3h, additional sodium triacetoxyborohydride (900 mg, 4.2 mol) and(S)-2-cyclohexylmethyl-4-oxo-butyric acid methyl ester (550 mg, 2.6mmol) were added in two portions, and the reaction mixture was stirredfor 1 h after the last addition. Saturated sodium bicarbonate (60 mL)was added, and the reaction mixture was extracted with dichloromethane(4×50 mL). The organic layer was dried with Na₂SO₄ and concentrated. Theresulting oil was dissolved in methanol (50 mL) and concentrated. Thecrude product was purified by preparative HPLC. Fractions containingpure product were pooled and the acetonitrile was removed at reducedpressure. Sodium carbonate (1.3 g, 12.3 mmol) was added and the productextracted into dichloromethane (3×200 mL). An additional portion ofsodium sulfate (15 g, 140 mmol) was added to the aqueous layer which wasextracted with dichloromethane (3×200 mL). The organic extracts werecombined, dried with Na₂SO₄ and concentrated to give the title compoundas the free base (1.16 g, 76% yield).

(m/z): [M+H]⁺ calcd for C₂₈H₄₄N₂O₄, 473.67; found, 473.4. ¹H NMR (CDCl₃,400 mHz) δ (ppm): 7.66 (d, J=1.8 Hz, 1H), 7.50 (dd, J=8.0 Hz, 1.9 Hz,1H), 7.13 (d, J=8.0 Hz, 1H), 3.65 (s, 3H), 3.58 (m, 1H), 3.47 (s, 3H),3.31 (dd, J=16.7, 6.1 Hz, 1H), 2.97 (m, 1H), 2.74-2.64 (m, 3H), 2.57 (m,1H), 1.90-1.53 (m, 14H), 1.33-1.11 (m, 6H), 0.89-0.83 (m, 3H), 0.69 (t,J=7.6 Hz, 3H), 0.59 (t, J=7.3 Hz, 3H).

Example 3(S)-4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid

A mixture of the product of Example 2 (685 mg, 1.43 mmol), 10 N NaOH(0.87 mL, 8.7 mmol), methanol (4.5 mL) and water (0.45 mL) was heated at55° C. for 2 h. The mixture was cooled to room temperature, diluted with50% aqueous acetic acid and purified by preparative HPLC. Cleanfractions were combined with those from another run (0.79 mmol scale)and lyophylized to give the title compound (1.02 g, 80% yield) as theTFA salt. (m/z): [M+H]⁺ calcd for C₂₇H₄₂N₂O₄, 459.32; found, 459.8. ¹HNMR (d₆-DMSO, 400 mHz) δ (ppm): 8.92 (br s, 1H), 7.97 (s, 1H), 7.70 (m,3H), 7.35 (s, 1H), 7.22 (d, J=8.4 Hz, 1H), 4.01 (m, 1H), 3.48 (dd,J=16.4, 5.7 Hz, 1H), 3.42 (s, 3H), 3.36 (m, 1H), 3.27 (m, 1H), 3.10 (m,1H), 2.70 (dd, J=16.8, 10.2 Hz, 1H), 2.43 (m, 1H), 2.15 (m, 1H), 1.90(m, 2H), 1.69-1.59 (m, 8H), 1.49 (m, 1H), 1.28-1.09 (m, 5H) 0.86, (m,2H), 0.66 (t, J=7.4 Hz, 3H), 0.58 (t, J=7.0 Hz, 3H).

Example 4(S)-4-(2R,3R)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid methyl ester

Following the procedure of Example 2 using(6R,7R)-7-amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydronaphthalene-2-carboxylicacid amide hydrochloride gave the title compound. (m/z): [M+H]⁺ calcdfor C₂₈H₄₄N₂O₄, 473.34; found, 473.4.

Example 5(R)-4-((2R,3R)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid methyl ester

(6R,7R)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide hydrochloride (0.16 g, 0.51 mmol) was dissolved indichloromethane (4.4 mL) and methanol (2 mL) at room temperature.(R)-2-Cyclohexylmethyl-4-oxo-butyric acid methyl ester (0.22 g, 1.0mmol) was added followed by triethylamine (0.071 mL, 0.51 mmol) andsodium triacetoxyborohydride (0.16 g, 0.77 mmol). Over the course of 2h, additional sodium triacetoxyborohydride (0.16 g) was added. Saturatedsodium bicarbonate was added and the reaction mixture was extracted withDCM. The organic extract was washed with brine (2×), dried over sodiumsulfate, filtered, and concentrated to dryness. The crude product wasdissolved in 1:1 AcOH/H₂O and was purified by preparative HPLC to givethe title compound as the TFA salt (161 mg, 53.6% yield). (m/z): [M+H]⁺calcd for C₂₈H₄₄N₂O₄, 473.33; found, 473.4. ¹H NMR (DMSO-d₆, 400 mHz) δ(ppm): 8.92 (bs, 1H), 7.95 (s, 1H), 7.70 (s, 2H), 7.68 (s, 1H), 7.33 (s,1H), 7.20 (d, J=8.4 Hz, 1H), 4.02-3.96 (m, 1H), 3.61 (s, 1H), 3.46 (dd,J=16.8, 5.87 Hz, 1H), 3.40 (s, 3H), 3.35-3.31 (m, 1H), 3.20-3.08 (m,2H), 2.68 (dd, J=16.4, 9.78 Hz, 1H), 2.51-2.58 (m, 1H), 2.16-2.11 (m,1H), 1.96-1.86 (m, 2H), 1.77-1.59 (m, 9H), 1.50-1.44 (m, 1H), 1.16-1.10(s, 4H), 0.88-0.83 (m, 2H), 0.64 (t, J=7.4 Hz, 3H), 0.56 (t, J=7.4 Hz,3H).

Example 6(R)-4-((2S,3SR)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid methyl ester

Following the procedure of Example 5 using(6S,7S)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide hydrochloride the title compound was prepared. (m/z): [M+H]calcd for C₂₈H₄₄N₂O₄, 473.33; found, 473.4. ¹H NMR (DMSO-d₆, 400 mHz) δ(ppm): 8.90 (bs, 1H), 7.96 (s, 1H), 7.74 (bs, 1H), 7.70 (s, 1H), 7.68(s, 1H), 7.32 (s, 1H), 7.20 (d, J=8.4 Hz, 1H), 4.04-4.97 (m, 1H), 3.60(s, 1H), 3.47 (dd, J=16.8, 5.67 Hz, 1H), 3.40 (s, 3H), 3.33-3.22 (m,2H), 3.03 (m, 1H), 2.69-2.57 (m, 2H), 2.17-2.11 (m, 1H), 1.99-1.96 (m,1H), 1.86-1.59 (m, 9H), 1.50-1.43 (m, 1H), 1.32-1.25 (m, 1H), 1.17-1.06(s, 4H), 0.89-0.80 (m, 2H), 0.64 (t, J=7.4 Hz, 3H), 0.56 (t, J=7.4 Hz,3H).

Example 7(S)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-4-methyl-pentanoicacid methyl ester (7-A) and(S)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-4-methyl-pentanoicacid (7-B)

(6S,7S)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide hydrochloride (0.19 g; 0.62 mmol) was dissolved in (3 mL) andmethanol (1.85 mL) at room temperature. (S)-2-Isobutyl-4-oxo-butyricacid methyl ester (0.212 g, 1.23 mmol) was added followed bytriethylamine (0.086 mL, 0.62 mmol), and then sodiumtriacetoxyborohydride (0.20 g, 0.92 mmol). Over the course of 3 h,additional (S)-2-isobutyl-4-oxo-butyric acid methyl ester (0.070 g) andsodium triacetoxyborohydride (0.15 g) were added. Saturated sodiumbicarbonate was added and the reaction mixture was extracted with DCM.The organic extract was dried with sodium sulfate, filtered, andconcentrated to dryness. The crude residue was dissolved in methanol (3mL) and 5 N NaOH (0.15 mL). The reaction mixture was heated at 50° C.for 17 h then cooled to room temperature, diluted with 1:1 AcOH/H₂O (3mL), and purified by preparative HPLC to give the TFA salts of the titlecompounds.

7-A: (35.3 mg, 10.2% yield over 2 steps). (m/z): [M+H]⁺ calcd forC₂₅H₄₀N₂O₄, 433.30; found, 433.4. ¹H NMR (DMSO-d₆, 400 mHz) δ (ppm):8.94 (bs, 1H), 7.95 (s, 1H), 7.69 (s, 2H), 7.68 (s, 1H), 7.29 (s, 1H),7.16 (d, J=8.6 Hz, 1H), 4.01 (m, 1H), 3.61 (s, 3H), 3.46 (dd, J=16.6,5.67 Hz, 1H), 3.40 (s, 3H), 3.35-3.30 (m, 1H), 3.12-3.09 (m, 2H), 2.67(dd, J=16.4, 9.78 Hz, 1H), 2.5 (m, 1H), 2.16-2.10 (m, 1H), 1.92-1.87 (m,2H), 1.78-1.59 (m, 3H), 1.52-1.45 (m, 2H), 1.29-1.22 (m, 1H), 0.85 (t,J=6.7, 6H), 0.63 (t, J=7.4 Hz, 3H), 0.56 (t, J=7.4 Hz, 3H).

7-B: (30 mg, 8.8% over 2 steps). (m/z): [M+H]⁺ calcd for C₂₄H₃₈N₂O₄,419.28; found, 419.6. ¹H NMR (DMSO-d₆, 400 mHz) δ (ppm): 12.42 (bs, 1H),8.89 (bs, 1H), 7.95 (s, 1H), 7.70 (s, 2H), 7.68 (s, 1H), 7.33 (s, 1H),7.19 (d, J=8.6 Hz, 1H), 4.0 (m, 1H), 3.49-3.47 (m, 1H), 3.40 (s, 3H),3.36-3.30 (m, 1H), 3.24 (bs, 1H), 3.1 (bs, 1H), 2.65 (dd, J=16.4, 9.78Hz, 1H), 2.42-2.41 (m, 1H), 2.16-2.10 (m, 1H), 1.94-1.81 (m, 2H),1.80-1.42 (m, 6H), 1.27-1.21 (m, 1H), 0.93-0.80 (m, 8H), 0.64 (t, J=7.4Hz, 3H), 0.56 (t, J=7.4 Hz, 3H).

Example 8

Following the procedure of Example 7 using the appropriate methyl esterin place of (S)-2-isobutyl-4-oxo-butyric acid methyl ester, TFA salts ofthe following compounds were prepared:

8-A:(R)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-4-methyl-pentanoicacid methyl ester: (m/z): [M+H]¹ calcd for C₂₅H₄₀N₂O₄, 433.30; found,433.6. ¹H NMR (DMSO-d₆, 400 mHz) δ (ppm): 8.84 (bs, 1H), 7.93 (s, 1H),7.68 (s, 2H), 7.66 (s, 1H), 7.31 (s, 1H), 7.18 (d, J=8.6 Hz, 1H), 3.98(m, 1H), 3.59 (s, 3H), 3.46 (dd, J=16.6, 5.28 Hz, 1H), 3.38 (s, 3H),3.32-3.23 (m, 2H), 3.02 (bs, 1H), 2.63 (dd, J=16.2, 9.4 Hz, 1H), 2.55(m, 1H), 2.16-2.10 (m, 1H), 1.97-1.95 (m, 1H), 1.83-1.59 (m, 3H),1.49-1.43 (m, 2H), 1.26-1.23 (m, 1H), 0.84 (t, J=6.1 Hz, 6H), 0.63 (t,J=7.4 Hz, 3H), 0.54 (t, J=7.4 Hz, 3H).

8-B:(R)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-4-methyl-pentanoicacid: (m/z): [M+H]⁺ calcd for C₂₄H₃₈N₂O₄, 419.28; found, 419.4. ¹H NMR(DMSO-d₆, 400 mHz) δ (ppm): 12.41 (bs, 1H), 8.88 (bs, 1H), 7.93 (s, 1H),7.68 (s, 2H), 7.66 (s, 1H), 7.31 (s, 1H), 7.18 (d, J=8.4 Hz, 1H),4.01-3.94 (m, 1H), 3.46 (dd, J=16.6, 16.6 Hz, 1H), 3.38 (s, 3H),3.32-3.26 (m, 1H), 3.04 (bs, 1H), 2.65 (dd, J=16.6, 9.79 Hz, 1H),2.42-2.37 (m, 1H), 2.15-2.02 (m, 1H), 1.95-1.92 (m, 1H), 1.81-1.42 (m,6H), 1.24-1.17 (m, 1H), 0.85 (t, J=6.2 Hz, 6H), 0.63 (t, J=7.4 Hz, 3H),0.54 (t, J=7.4 Hz, 3H).

8-C:(R)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-3-methyl-butyricacid methyl ester: (m/z): [M+H]⁺ calcd for C₂₄H₃₈N₂O₄, 419.28; found,419.4.

8-D:(R)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-3-methyl-butyricacid: (m/z): [M+H]⁺ calcd for C₂₃H₃₆N₂O₄, 405.27; found, 405.4. ¹H NMR(DMSO-d₆, 400 mHz) δ (ppm): 112.39 (bs, 1H), 8.92 (bs, 1H), 7.94 (s,1H), 7.68 (s, 2H), 7.67 (s, 1H), 7.32 (s, 1H), 7.19 (d, J=8.4 Hz, 1H),4.01-3.96 (m, 1H), 3.46 (dd, J=16.6, 5.68 Hz, 1H), 3.39 (s, 3H),3.34-3.31 (m, 1H), 3.25 (bs, 1H), 3.04 (bs, 1H), 2.64 (dd, J=16.4, 9.59Hz, 1H), 2.23-2.09 (m, 2H), 1.98-1.59 (m, 6H), 0.89-0.86 (m, 4H), 0.63(t, J=7.4 Hz, 3H), 0.55 (t, J=7.4 Hz, 3H).

8-E:(R)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-4,4-dimethyl-pentanoicacid methyl ester: (m/z): [M+H]⁺ calcd for C₂₆H₄₂N₂O₄, 447.31; found,447.6.

8-F:(R)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-4,4-dimethyl-pentanoicacid: (m/z): [M+H]⁺ calcd for C₂₅H₄₀N₂O₄, 433.30; found, 433.2. ¹H NMR(DMSO-d₆, 400 mHz) δ (ppm): 8.90 (bs, 1H), 7.94 (s, 1H), 7.69 (s, 2H),7.67 (s, 1H), 7.32 (s, 1H), 7.19 (d, J=8.4 Hz, 1H), 4.01-3.94 (m, 1H),3.46 (dd, J=17.0, 5.87 Hz, 1H), 3.39 (s, 3H), 3.33-3.27 (m, 1H), 3.25(bs, 1H), 3.03 (bs, 1H), 2.64 (dd, J=16.4, 9.78 Hz, 1H), 2.31-2.35 (m,H), 2.16-2.10 (m, 1H), 1.97-1.94 (m, 1H), 1.80-1.57 (m, 5H), 1.18 (dd,J=13.8, 2.93 Hz, 1H), 0.85 (m, 9H), 0.65 (t, J=7.4 Hz, 3H), 0.54 (t,J=7.4 Hz, 3H).

Example 9(S)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-heptanoicacid

(6S,7S)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide hydrochloride (0.20 g; 0.64 mmol) was dissolved indichloromethane (3 mL) and methanol (1.92 mL) at room temperature.(S)-2-Pentyl-4-oxo-butyric acid methyl ester (0.24 g, 1.3 mmol) wasadded followed by triethylamine (0.089 mL, 0.64 mmol) and sodiumtriacetoxyborohydride (0.20 g, 0.96 mmol). Over the course of 90 min,additional sodium triacetoxyborohydride (0.070 g, 0.33 mmol) was added.Saturated sodium bicarbonate was added and the reaction mixture wasextracted with DCM. The organic layer was dried with sodium sulfate,filtered, and concentrated to dryness (0.40 g). The crude residue wasdissolved in MeOH (3 mL) and 5 N NaOH (0.40 mL) was added. The reactionmixture was heated at 50° C. for 5 h, then cooled at room temperaturewhile stirring overnight. The crude reaction mixture was diluted with1:1 AcOH/H₂O (3 mL) and purified by preparative HPLC to give the titlecompound as the TFA salt (32 mg, 8.8% over 2 steps). (m/z): [M+H]⁺ calcdfor C₂₅H₄₀N₂O₄, 433.30; found, 433.4. ¹H NMR (DMSO-d₆, 400 mHz) δ (ppm):7.91 (s, 1H), 7.66 (s, 2H), 7.64 (s, 1H), 7.29 (s, 1H), 7.16 (d, J=8.6Hz, 1H), 3.97-3.91 (m, 1H), 3.43 (dd, J=16.4, 5.48 Hz, 1H), 3.36 (s,3H), 3.31-3.17 (m, 2H), 3.02 (m, 1H), 2.63 (dd, J=16.4, 9.78 Hz, 1H),2.34-2.26 (m, 1H), 2.12-2.00 (m, 1H), 1.88-1.82 (m, 2H), 1.74-1.51 (m,3H), 1.49-1.36 (m, 2H), 1.20 (s, 6H), 0.80 (t, J=6.7, 4H), 0.60 (t,J=7.4 Hz, 3H), 0.52 (t, J=7.4 Hz, 3H).

Example 10

Following the procedure of Example 9 using the appropriate methyl esterin place of (S)-2-pentyl-4-oxo-butyric acid methyl ester, TFA salts ofthe following compounds were prepared:

10-A:(S)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-5-phenyl-pentanoicacid: (m/z): [M+H]⁺ calcd for C₂₉H₄₀N₂O₄, 481.30; found, 481.4. ¹H NMR(DMSO-d₆, 400 mHz) δ (ppm): 12.39 (bs, 1H), 8.87 (bs, 1H), 7.92 (s, 1H),7.65 (m, 3H), 7.29 (s, 1H), 7.22-7.05 (m, 7H), 3.98-3.91 (m, 1H), 3.43(dd, J=16.6, 5.67 Hz, 1H), 3.35 (s, 3H), 3.31-3.17 (m, 2H), 3.04 (bs,1H), 2.63 (dd, J=16.6, 9.59 Hz, 1H), 2.52 (t, J=6.6 Hz, 2H), 2.34 (m,1H), 2.12-2.06 (m, 1H), 1.88-1.82 (m, 2H), 1.74-1.41 (m, 7H), 1.49-1.36(m, 2H), 1.20 (s, 6H), 0.80 (t, J=6.7, 3H), 0.60 (t, J=7.4 Hz, 3H),0.514 (t, J=7.4 Hz, 3H).

10-B:(S)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-4,4-dimethyl-pentanoicacid: (m/z): [M+H]⁺ calcd for C₂₅H₄₀N₂O₄, 433.30; found, 433.6. ¹H NMR(DMSO-d₆, 400 mHz) δ (ppm): 12.39 (bs, 1H), 8.87 (bs, 1H), 7.93 (s, 1H),7.66 (s, 2H), 7.64 (s, 1H), 7.31 (s, 1H), 7.18 (d, J=8.2 Hz, 1H), 3.96(m, 1H), 3.43 (dd, J=16.8, 5.87 Hz, 1H), 3.38 (s, 3H), 3.29 (bs, 1H),3.18-3.10 (m, 1H), 2.66 (dd, J=16.4, 9.97 Hz, 1H), 2.32 (m, 1H),2.14-2.08 (m, 1H), 1.87 (m, 2H), 1.76-1.58 (m, 4H), 1.18 (m, 1H), 0.84(s, 9H), 0.62 (t, J=7.4 Hz, 3H), 0.54 (t, J=7.4 Hz, 3H).

10-C:(S)-2-Benzyl-4-((2S,3S)-7-carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-butyricacid: (m/z): [M+H]⁺ calcd for C₂₇H₃₆N₂O₄, 453.27; found, 453.1. ¹H NMR(DMSO-d₆, 400 mHz) δ (ppm): 8.86 (bs, 1H), 7.93 (s, 1H), 7.68 (s, 1H),7.67 (s, 2H), 7.31-7.16 (m, 5H), 7.17 (d, J=8.2 Hz, 1H), 4.0-3.93 (m,1H), 3.46 (dd, J=16.8, 5.87 Hz, 1H), 3.38 (s, 3H), 3.35-3.26 (m, 2H),3.04 (bs, 1H), 2.91-2.86 (m, 1H), 2.76-2.61 (m, 2H), 2.17-2.07 (m, 1H),1.89-1.83 (m, 2H), 1.72-1.55 (m, 3H), 0.61 (t, J=7.4 Hz, 3H), 0.51 (t,J=7.4 Hz, 3H).

10-D:(R)-2-[2-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-ethyl]-hexanoicacid: (m/z): [M+H]⁺ calcd for C₂₇H₃₆N₂O₄, 419.28; found, 419.3. ¹H NMR(DMSO-d₆, 400 mHz) δ (ppm): 7.97 (s, 1H), 7.72 (s, 2H), 7.70 (s, 1H),7.34 (s, 1H), 7.22 (d, J=8.1 Hz, 1H), 4.04-3.98 (m, 1H), 3.48 (dd,J=16.8, 5.68 Hz, 1H), 3.42 (s, 3H), 3.37-3.25 (m, 2H), 3.09-3.05 (m,1H), 2.68 (dd, J=16.6, 9.78 Hz, 1H), 2.44-2.40 (m, 1H), 2.29-2.13 (m,1H), 2.01-1.98 (m, 1H), 1.86-1.62 (m, 4H), 1.55-1.46 (m, 2H), 1.34-1.22(m, 6H), 0.87 (t, J=6.8, 4H), 0.66 (t, J=7.4 Hz, 3H), 0.58 (t, J=7.4 Hz,3H).

10-E:(S)-4-((2R,3R)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid: (m/z): [M+H]⁺ calcd for C₂₇H₄₂N₂O₄, 459.31; found, 459.4. ¹H NMR(DMSO-d₆, 400 mHz) δ (ppm): 12.42 (bs, 1H), 8.84 (bs, 1H), 7.95 (s, 1H),7.69-7.65 (m, 3H), 7.33 (s, 1H), 7.20 (d, J=8.6 Hz, 1H), 4.04-3.96 (m,1H), 3.47 (dd, J=16.8, 5.86 Hz, 1H), 3.40 (s, 3H), 3.35-3.22 (m, 2H),3.06 (bs, 1H), 2.66 (dd, J=16.4, 9.39 Hz, 1H), 2.32 (m, 1H), 2.17-2.12(m, 1H), 1.96-1.90 (m, 1H), 1.81-1.60 (m, 9H), 1.50-1.44 (m, 1H),1.29-1.07 (m, 5H), 0.91-0.81 (m, 2H), 0.64 (t, J=7.4 Hz, 3H), 0.55 (t,J=7.4 Hz, 3H).

10-F:(R)-4-((2R,3R)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid: m/z): [M+H]⁺ calcd for C₂₇H₄₂N₂O₄, 459.31; found, 459.8.

10-G:(R)-4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid: (m/z): [M+H] calcd for C₂₇H₄₂N₂O₄, 459.31; found, 459.4. ¹H NMR(DMSO-d₆, 400 mHz) δ (ppm): 12.4 (bs, 1H), 8.82 (bs, 1H), 7.91 (s, 1H),7.66-7.61 (m, 3H), 7.29 (s, 1H), 7.16 (d, J=8.4 Hz, 1H), 4.06-3.93 (m,1H), 3.43 (dd, J=17.2, 6.06 Hz, 1H), 3.36 (s, 3H), 3.31-3.25 (m, 2H),3.0 (bs, 1H), 2.65-2.58 (m, 1H), 2.13-2.07 (m, 1H), 1.89 (m, 1H),1.71-1.57 (m, 9H), 1.45-1.41 (m, 1H), 1.28-1.03 (m, 5H), 0.86-0.78 (m,2H), 0.61 (t, J=7.4 Hz, 3H), 0.52 (t, J=7.4 Hz, 3H).

Example 11trans-(S)-4-(7-Carbamoyl-3-methoxy-1,1-diethyl-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexyl-butyricacid

Following the procedure of Example 9 using(S)-2-cyclohexyl-4-oxo-butyric acid methyl ester and the racemiccompoundtrans-7-amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide hydrochloride, the TFA salt of the title compound wasprepared. (m/z): [M+H]⁺ calcd for C₂₆H₄₀N₂O₄, 445.30; found, 445.4

Example 12(S)-2-Cyclohexylmethyl-4-((2S,3S)-1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-butyricacid a.(S)-2-Cyclohexylmethyl-4-((2S,3S)-1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-butyricacid methyl ester

To a slurry of sodium(S)-4-cyclohexyl-1-hydroxy-3-methoxycarbonyl-butane-1-sulfonate (158 mg,0.5 mmol) in 2-MeTHF (2 mL) was added 2N NaOH (0.22 mL, 0.44 mmol). Thereaction mixture was stirred for 20 min at which time all of the solidshad dissolved.(6S,7S)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-olhydrochloride (100 mg, 0.35 mmol) was added and the mixture was stirredat RT for 30 min. Sodium triacetoxyborohydride (425 mg, 2.0 mmol) wasadded in 4 portions over 3 h. Thirty minutes after the last addition,EtOAc (15 mL) was added and the mixture was washed with 5% aqueoussodium carbonate (2×5 mL) and saturated sodium chloride (5 mL). Theorganic layer was dried with Na₂SO₄ and concentrated to give the titlecompound (159 mg). (m/z): [M+H]⁺ calcd for C₂₇H₄₃NO₄, 446.33; found,446.6.

b.(S)-2-Cyclohexylmethyl-4-((2S,3S)-1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-butyricacid

A solution of the product of the previous step (159 mg, 0.36 mmol),methanol (1.5 mL), water (0.20 mL) and 10 N NaOH (0.21 mL, 2.1 mmol) washeated at 50° C. After 4 h, the reaction mixture was cooled to roomtemperature, diluted with 50% aqueous acetic acid, and purified bypreparative HPLC to give the title compound as the TFA salt (110 mg, 58%yield over 2 steps). (m/z): [M+H] calcd for C₂₆H₄₁NO₄, 432.31; found,432.8. ¹H NMR (CD₃OD, 400 mHz) δ (ppm): 6.97 (d, J=8.2 Hz, 1H), 6.65(dd, J=8.4, 2.5 Hz, 1H), 6.62 (d, J=2.4 Hz, 1H), 4.01 (m, 1H), 3.48 (s,3H), 3.47-3.37 (m, 3H), 3.22 (m, 1H), 2.58 (dd J=15.9, 10.2 Hz, 2H),2.10 (m, 1H), 1.97 (m, 2H), 1.82-1.60 (m, 10H), 1.37-1.18 (m, 6H), 0.92(m, 2H), 0.80 (t, J=7.4 Hz, 3H), 0.71 (t, J=7.2 Hz, 3H).

Example 13(S)-2-Cyclohexylmethyl-4-((2R,3R)-1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-butyricacid

Following the procedure of Example 12 using(6R,7R)-7-amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-olhydrochloride in step (a), the title compound was prepared. (m/z): [M+H]calcd for C₂₆H₄₁NO₄, 432.31; found, 432.8. ¹H NMR (CD₃OD, 400 mHz) δ(ppm): 6.97 (d, J=8.2 Hz, 1H), 6.65 (dd, J=8.3, 2.5 Hz, 1H), 6.62 (d,J=2.6 Hz, 1H), 4.01 (m, 1H), 3.48 (s, 3H), 3.47-3.37 (m, 3H), 3.20 (m,1H), 2.58 (dd J=16.0, 10.0 Hz, 2H), 2.13-1.95 (m, 2H), 1.95-1.60 (m,10H), 1.38-1.19 (m, 6H), 0.92 (m, 2H), 0.80 (t, J=7.4 Hz, 3H), 0.71 (t,J=7.3 Hz, 3H).

Example 14(R)-2-Cyclohexylmethyl-4-((2S,3S)-1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-butyricacid a.(R)-2-Cyclohexylmethyl-4-((2S,3S)-1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-butyricacid methyl ester

(6S,7S)-7-Amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-olhydrochloride salt (100 mg, 0.35 mmol),(R)-2-cyclohexylmethyl-4-oxo-butyric acid methyl ester (90 mg, 0.42mmol) and triethylamine (35 mg, 0.035 mmol) were dissolved indichloromethane (2.0 mL) and stirred at room temperature for 30 min.Sodium triacetoxyborohydride (1.03 g, 4.85 mmol) was added and thereaction was monitored by HPLC. After 3 h, additional(R)-2-cyclohexylmethyl-4-oxo-butyric acid methyl ester (20 mg, 0.1 mmol)and sodium triacetoxyborohydride (30 mg, 0.14 mmol) were added. Thirtyminutes after the last addition, EtOAc (15 mL) was added and the mixturewas washed with 5% aqueous sodium carbonate (2×5 mL) and saturatedsodium chloride (5 mL). The organic layer was dried with Na₂SO₄) andconcentrated to give the title compound (190 mg). (m/z): [M+H]⁺ calcdfor C₂₇H₄₃NO₄, 446.33; found, 446.6.

b.(R)-2-Cyclohexylmethyl-4-((2S,3S)-1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-butyricacid

Following the procedure of Example 12 step (b), the TFA salt of thetitle compound was isolated. (m/z): [M+H]⁺ calcd for C₂₆H₄₁NO₄, 432.31;found, 432.8. ¹H NMR (CD₃OD, 400 mHz) δ (ppm): 6.97 (d, J=8.5 Hz, 1H),6.65 (dd, J=8.3, 2.3 Hz, 1H), 6.62 (d, J=2.3 Hz, 1H), 4.01 (m, 1H), 3.48(s, 3H), 3.47-3.37 (m, 3H), 3.22 (m, 1H), 2.58 (dd J=16.0, 10.0 Hz, 2H),2.15-1.95 (m, 2H), 1.95-1.60 (m, 10H), 1.38-1.18 (m, 6H), 0.92 (m, 2H),0.80 (t, J=7.6 Hz, 3H), 0.71 (t, J=7.5 Hz, 3H).

Example 15(R)-2-Cyclohexylmethyl-4-((2R,3R)-1,1-diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-butyricacid

Following the procedure of Example 14 using(6R,7R)-7-amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalen-2-olhydrochloride in step (a), the title compound was prepared. (m/z):[M+H]⁺ calcd for C₂₆H₄₁NO₄, 432.31; found, 432.8. ¹H NMR (CD₃OD, 400mHz) δ (ppm): 6.97 (d, J=8.2 Hz, 1H), 6.65 (dd, J=8.5, 2.5 Hz, 1H), 6.62(d, J=2.3 Hz, 1H), 4.01 (m, 1H), 3.48 (s, 3H), 3.47-3.37 (m, 3H), 3.22(m, 1H), 2.58 (dd J=15.7, 10.2 Hz, 2H), 2.10 (m, 1H), 1.98 (m, 2H),1.79-1.60 (m, 10H), 1.37-1.18 (m, 6H), 0.92 (m, 2H), 0.80 (t, J=7.4 Hz,3H), 0.71 (t, J=7.2 Hz, 3H).

Example 16

Following the procedure of Example 9 using the appropriate methyl esterin place of (S)-2-pentyl-4-oxo-butyric acid methyl ester and the racemiccompoundtrans-7-amino-8,8-dimethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide.hydrochloride, the TFA salts of the following compounds wereprepared:

16-A:trans-(S)-4-(7-Carbamoyl-1,1-dimethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid: (m/z): [M+H]⁺ calcd for C₂₅H₃₈N₂O₄, 431.28; found, 431.2

16-B:trans-(S)-4-(7-Carbamoyl-3-methoxy-1,1-dimethyl-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexyl-butyricacid: (m/z): [M+H]⁺ calcd for C₂₄H₃₆N₂O₄, 417.27; found, 417.4.

Example 17(S)-4-(2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid a.(S)-4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid benzyl ester hydrochloride

To a suspension of sodium(S)-3-benzyloxycarbonyl-4-cyclohexyl-1-hydroxy-butane-1-sulfonate (160g, 400 mmol), the product of Preparation 17, in MeTHF (2.0 L) and water(600 mL) was added 1.0 M NaOH in water (400 mL) and the reaction mixturewas stirred at room temperature for 90 min. Phases were separated andthe solution was concentrated to a volume of ˜300 mL.

The resulting concentrated solution was added to a slurry of(6S,7S)-7-amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide hydrochloride (100.0 g, 319.7 mmol) in DMF (1 L). Resultingslurry was stirred at room temperature for 2 h, the reaction mixture wascooled to 0° C. followed by portion-wise addition of sodiumtriacetoxyborohydride (169 g, 799 mmol) over 15 min. The reactionmixture was stirred at RT overnight, cooled to 10° C. and then 1.0 MNaOH in water (3 L) and ethyl acetate (5 L) were added. The reactionmixture was stirred for 10 min, phases were separated, and the organiclayer was washed with diluted brine (1:1, 2 L). To the organic layer wasadded 1.0 M HCl in water (520 mL, 520 mmol) and most of the ethylacetate was removed by rotary evaporation. Water (500 mL) and ethanol (1L) were added and the volume was slowly reduced by rotary evaporation to˜1 L. The resulting off-white free-flowing slurry was stirred at RTovernight. Product was isolated by filtration, flask and filter cakewere washed with water (2×200 mL) and then dried to yield the titlecompound (175 g) as a white solid (˜99% purity, 90% yield based onaminotetralin reagent). ¹H NMR (400 MHz, DMSO-d₆): δ (ppm) 9.33 (br,1H), 8.09 (br, 1H), 7.98 (s, 1H), 7.70 (s, 1H), 7.68 (d, 1H), 7.28-7.36(m, 2H), 7.19 (d, 1H), 5.10 (q, 2H), 4.04 (m, 1H), 3.45 (dd, 1H), 3.38(s, 3H), 3.25 (m, 2H), 3.05 (m, 1H), 2.62 (m, 2H), 1.95-2.15 (m, 2H),1.61-1.82 (m, 3H), 1.50-1.61 (m, 4H), 1.42-1.50 (m, 1H), 1.24-1.32 (m,1H), 0.98-1.18 (m, 4H), 0.71-0.89 (m, 2H), 0.63 (t, 3H), 0.52 (t, 3H).

b.(S)-4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid

The product of the previous step (175.0 g, 299 mmol) was partitionedbetween ethyl acetate (2.5 L), water (1 L) and 1.0 M NaOH in water (300mL, 299 mmol). Phases were separated, the organic layer was washed withdiluted brine (1:1, 250 mL), and dried with sodium sulfate. Solvent wasremoved by rotary evaporation and the resulting product dried overnightunder high vacuum to provide the free-base intermediate(S)-4-((2S,3S)-7-carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid benzyl ester (˜160 g) as a sticky solid.

The free-base intermediate was dissolved in a mixture of acetonitrile(1.6 L) and water (300 mL). To half of the solution (1 L) was added 10%palladium (10 g, 9 mmol) on carbon (wet). The reaction mixture waspurged with nitrogen and then with hydrogen for 2 min and then exposedto 10-15 psi H₂ for 3 h at RT. The reaction mixture was filtered throughcelite, and the flask and filter cake were washed with acetonitrile (50mL). The yellowish filtrate was stirred with thiol-modified silica (10g) at RT for 2 h and then filtered through celite. Most of the solventwas removed by rotary evaporation at 25° C. Acetonitrile (500 mL) wasadded and most of the solvent was removed by rotary evaporation.Additional acetonitrile (500 mL) was added resulting in fastprecipitation of sticky solids. The reaction mixture was stirredvigorously at room temperature overnight resulting in a free-flowingoff-white slurry. Product was isolated by filtration; the filter cakewas washed with acetonitrile (2×50 mL) and then dried under vacuum toyield the title compound as a crystalline solid (56 g, 98.8% purity).Water content 0.49% (w/w). ¹H NMR (400 MHz, DMSO-d₆): δ (ppm) 7.89 (br,1H), 7.65 (s, 1H), 7.60 (d, 1H), 7.22 (br, 1H), 7.11 (d, 1H), 3.55 (m,1H), 3.38 (s, 3H), 3.25 (dd, 1H), 2.95 (m, 1H), 2.59 (d, 1H), 2.49 (m,2H), 1.81 (m, 2H), 1.49-1.63 (m, 5H), 1.41-1.50 (m, 2H), 1.05-1.25 (m,4H), 0.72-0.90 (m, 2H), 0.45 (t, 3H), 0.57 (t, 3H).

Example 184-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-(trans-4-hydroxy-cyclohexylmethyl)-butyricacid (A) and4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-(cis-4-hydroxy-cyclohexylmethyl)-butyricacid (B)

a. 2-[4-(tert-Butyl-dimethyl-silanyloxy)-cyclohexylmethylene]-succinicacid 1-methyl ester

A solution of dimethyl succinate (730 mg, 5.0 mmol) and4-(tert-butyl-dimethyl-silanyloxy)-cyclohexanecarbaldehyde (1.00 g, 4.1mmol) was added over 25 min to a 1.0M solution of potassiumtert-butoxide in tert-butanol (4.4 mL. 4.4 mmol). The reaction mixturewas heated at 50° C. for 50 min, cooled to RT and concentrated undervacuum. The residue was dissolved in water (25 mL) and washed with EtOAc(2×10 mL). The aqueous layer was acidified with 6 N HCl (2.0 mL, 12mmol) and extracted with EtOAc (2×20 mL), dried (Na₂SO₄) andconcentrated. The crude product was purified by flash chromatography(25% EtOAc/DCM) to give the title compound (560 mg) as a mixture ofolefin isomers (˜1:1) and a mixture of cis and trans isomers at thecyclohexyl ring (˜1:1). ¹H NMR (CDCl₃, 400 mHz) δ (ppm) olefin peaks at6.88 (d, J=10.2 Hz) 6.77 (d, J=10.0 Hz) CHOTBS peaks at 3.96 ppm (br s)(cis isomer, hydrogen equatorial, 3.55 (m) (trans isomer, hydrogenaxial).

b. 2-[4-(tert-Butyl-dimethyl-silanyloxy)-cyclohexylmethyl]-succinic acid1-methyl ester

To a solution of the product of the previous step (560 mg, 1.6 mmol) inEtOAc (15 mL) was added 10% Pd/C (50% water, 165 mg dry weight). Thereaction was shaken under 50 psi hydrogen for 16 h. The reaction wasfiltered through Celite, rinsing with EtOAc (5×5 mL), MeOH (3×5 mL) andDCM (3×5 mL). The combined filtrates were concentrated to dryness atreduced pressure. The crude product was purified by flash chromatography(25% EtOAc/DCM) to give the title compound (245 mg) as a ˜1:1 mixture ofcis and trans isomers at the cyclohexyl ring. ¹H NMR (CDCl₃, 400 mHz) δ(ppm) CHOTBS peaks at 3.92 ppm (br s) (cis isomer, hydrogen equitorial),3.50 (m) (trans isomer, hydrogen axial)

c.2-[4-(tert-Butyl-dimethyl-silanyloxy)-cyclohexylmethyl]-4-hydroxy-butyricacid methyl ester

A solution of the product of the previous step (245 mg, 0.683 mmol) inTHF (2.0 mL) was cooled in ice and a solution of borane in 1.0 M THF(1.4 mL) was added over 5 min. The reaction was stirred at 0° C. for 1.5h, and then quenched by the dropwise addition of MeOH (10 mL). Themixture was concentrated under reduced pressure. Additional MeOH (10 mL)was added and the mixture was concentrated under reduced pressure togive the crude title product (228 mg) which was used immediately in thenext step.

d. 2-[4-(tert-Butyl-dimethyl-silanyloxy)-cyclohexylmethyl]-4-oxo-butyricacid methyl ester

The product of the previous step (228 mg, 0.66 mmol) was dissolved inDCM (7.0 mL). DMSO (218 mg, 2.8 mmol) and DIPEA (361 mg, 2.8 mmol) wereadded and the mixture was cooled to −10° C. Sulfur trioxide pyridinecomplex (223 mg, 1.4 mmol) was added as a solid, and the reaction wasstirred at −10° C. for 1.5 h. DCM (20 mL) was added, followed by 0.5 NHCl (10 mL). Layers were separated and the aqueous layer was extractedwith DCM (2×10 mL). The combined organic layers were washed with water(3×10 mL) and saturated NaCl (10 mL), then dried (Na₂SO₄) andconcentrated to give the title compound (220 mg). ¹H NMR (CDCl₃, 400mHz) showed aldehyde peaks at 9.81 and 9.75 ppm.

e.2-[4-(tert-Butyl-dimethyl-silanyloxy)-cyclohexylmethyl]-4-((2S,3S)-7-carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-butyricacid methyl ester

A solution of(6S,7S)-7-amino-8,8-diethyl-6-methoxy-5,6,7,8-tetrahydro-naphthalene-2-carboxylicacid amide (100 mg, 0.32 mmol), the product of the previous step (140mg, 0.41), triethylamine (33 mg, 0.33 mmol) in DCM (2.0 mL) and MeOH(0.5 mL) was stirred at RT for 35 min. Sodium triacetoxyborohydride (135mg, 0.64 mmol) was added and the reaction was monitored by HPLC.Additional portions of sodium triacetoxyborohydride were added at 1 h(50 mg) and 1.5 h (100 mg), and an additional portion of the aldehydewas added at 1.75 h (80 mg). Fifteen minutes after the last addition,DCM (20 mL) and saturated NaHCO₃ (10 mL) were added. The layers wereseparated and the aqueous layer was extracted with DCM (2×10 mL). Thecombined organic extracts were dried (Na₂SO₄) and concentrated to givethe crude title product (283 mg).

f.4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-(trans-4-hydroxy-cyclohexylmethyl)-butyricacid methyl ester (f1) and4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-(cis-4-hydroxy-cyclohexylmethyl)-butyricacid methyl ester (f2)

A portion of the crude product of the previous step (28 mg, 0.32 mmol)was dissolved in 50% aqueous AcOH (0.5 mL). After 16 h, the productswere separated by preparative HPLC to give the title compounds.

f1 (first eluting) (3.3 mg) (m/z): [M+H]⁺ calcd for C₂₈H₄₄N₂O₅ 489.33;found 489.6. ¹H NMR (CD₃OD, 400 mHz) δ (ppm) 7.71 (d, J=1.6 Hz, 1H),7.65 (d, J=8.0, 1H), 7.20 (d, J=8.0 Hz, 1H), 4.02 (m, 1H), 3.63 (s, 3H),3.51 (dd, J=16.5, 5.5 Hz, 1H), 3.44 (s, 3H), 3.44-3.30 (m, 3H), 3.14 (m,1H), 2.70 (m, 1H), 2.54 (m, 1H), 2.24 (m, 1H), 2.00-1.50 (m, 9H), 1.30(m, 2H), 1.12 (m, 3H), 0.91 (m, 2H), 0.71 (t, J=7.5 Hz, 3H), 0.62 (t,J=7.2 Hz).

f2 (second eluting) (7.3 mg) (m/z): [M+H]⁺ calcd for C₂₈H₄₄N₂O₅ 489.33;found 489.6. ¹H NMR (CD₃OD, 400 mHz) δ (ppm) 7.71 (d, J=1.6 Hz, 1H),7.65 (dd, J=8.0, 1.4 Hz, 1H), 7.20 (d, J=8.2 Hz, 1H), 4.02 (m, 1H), 3.79(br s, 1H) 3.62 (s, 3H), 3.51 (dd, J=16.7, 5.7 Hz, 1H), 3.44 (s, 3H),3.44-3.30 (m, 2H), 3.15 (m, 1H), 2.68 (m, 1H), 2.57 (m, 1H), 2.24 (m,1H), 2.05-1.80 (m, 2H), 1.70-1.55 (m, 6H), 1.50-1.10 (m, 8H), 0.71 (t,J=7.4 Hz, 3H), 0.62 (t, J=7.3 Hz, 3H).

g.4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-(trans-4-hydroxy-cyclohexylmethyl)-butyricacid (A)

To a solution of4-((2S,3S)-7-carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-(trans-4-hydroxy-cyclohexylmethyl)-butyricacid methyl ester (f1) (27.4 mg, 0.045 mmol) in MeOH (0.50 mL) was addedwater (32 μL) and 10N NaOH (32 μL, 0.32 mmol). The mixture was heated at50° C. After 15 h, the reaction mixture was cooled to RT, dissolved in50% aqueous AcOH (6 mL) and purified by preparative HPLC to give thetitle compound (13.8 mg) as a lyophylized powder. (m/z): [M+H] calcd forC₂₇H₄₂N₂O₅ 475.32; found 475.2. ¹H NMR (CD₃OD, 400 mHz) δ (ppm) 7.78 (d,J=1.6 Hz, 1H), 7.72 (dd, J=8.0 Hz, 1.7 Hz, 1H), 7.28 (d, J=8.2 Hz, 1H),4.09 (m, 1H), 3.57 (dd, J=16.7, 5.9 Hz, 1H), 3.52 (s, 3H), 3.52-3.42 (m,3H), 3.23 (m, 1H), 2.78 (m, 1H), 2.58 (m, 1H), 2.31 (m, 1H), 2.05-1.60(m, 10H), 1.40-1.15 (m, 4H), 1.00 (m. 2H), 0.79 (t, J=7.5 Hz, 3H), 0.70(dt, J=7.3, 1.3 Hz, 3H).

h.4-((2S,3S)-7-Carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-(cis-4-hydroxy-cyclohexylmethyl)-butyricacid (B)

To a solution of4-((2S,3S)-7-carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-(cis-4-hydroxy-cyclohexylmethyl)-butyricacid methyl ester (f2) (56 mg, 0.11 mmol) in MeOH (0.50 mL) was addedwater (66 μL) and 10 N NaOH (66 μL, 0.66 mmol). The mixture was heatedat 50° C. After 15 h, the reaction mixture was cooled to RT, dissolvedin 50% aqueous AcOH (6 mL) and purified by preparative HPLC to give thetitle compound (54 mg) as a lyophylized powder. (m/z): [M+H] calcd forC₂₇H₄₂N₂O₅ 475.32; found 475.2. ¹H NMR (CD₃OD, 400 mHz) δ (ppm) 7.78 (d,J=1.8 Hz, 1H), 7.72 (dd, J=8.0 Hz, 1.7 Hz, 1H), 7.28 (d, J=8.0 Hz, 1H),4.09 (m, 1H), 3.88 (br s, 1H), 3.58 (dd, J=16.6, 5.6 Hz, 1H), 3.52 (s,3H), 3.52-3.46 (m, 2H) 3.30-3.20 (m, 1H), 2.77 (m, 1H), 2.59 (m, 1H),2.31 (m, 1H), 2.05-1.92 (m, 2H), 1.79-1.65 (m, 6H), 1.60-1.35 (m, 8H),0.79 (t, J=7.5 Hz, 3H), 0.70 (dt, J=7.2, 1.6 Hz).

Example 19 Metabolite Study

A sample of(S)-4-((2S,3S)-7-carbamoyl-1,1-diethyl-3-methoxy-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-2-cyclohexylmethyl-butyricacid, the compound of Example 1, was incubated for 4 h at 37° C. withcryopreserved human hepatocytes in DMSO at a concentration of 1.2million cells/mL. Aliquots of the resulting solution were mixed with onevolume of 97% acetonitrile/3% TFA and frozen at −20° C. Upon thawing,samples were centrifuged for 10 min at 20,800×g and 4° C. Supernatantswere collected, diluted with 3 volumes of water and analyzed by HPLCcoupled with mass spectrometry (LC/MS) under the conditions describedbelow. For metabolite identification, aliquots after dilution werecombined separately with compound A and with compound B of Example 18and analyzed by LC/MS. The resulting ion extraction chromatograms at475.3±0.5 a.m.u. are consistent with the interpretation that theprincipal hydroxyl metabolite of the compound of Example 1, is thetrans-4-hydroxy compound A, although the cis-4-hydroxy compound B cannotbe ruled out.

Agilent model 1100 HPLC with Luna C18(2) 100 A 5 μm column; flow rate:0.25 mL/min; Solvent A: 95% water, 5% acetonitrile, 0.05% TFA; SolventB: >95% acetonitrile, 5% water, 0.05% TFA; Gradient (time(min)/% B):0/7, 5/7, 60/25, 61/100, 63.5/100, 64/7, 70/7. Applied Biosystems modelAPI3000 triple quadrupole mass spectrometer.

Assay 1: Radioligand Binding Assay on Human Mu, Human Delta and GuineaPig Kappa Opioid Receptors a. Membrane Preparation

CHO-K1 (Chinese Hamster Ovary) cells stably transfected with human muopioid or with guinea pig kappa receptor cDNA were grown in mediumconsisting of Ham's-F12 media supplemented with 10% FBS, 100 units/mlpenicillin—100 μg/mL streptomycin and 800 μg/mL Geneticin in a 5% CO₂,humidified incubator @37° C. Receptor expression levels (B_(max) ˜2.0and ˜0.414 pmol/mg protein, respectively) were determined using[³H]-Diprenorphine (specific activity ˜50-55 Ci/mmol) in a membraneradioligand binding assay.

Cells were grown to 80-95% confluency (<25 subculture passages). Forcell line passaging, the cell monolayer was incubated for 5 minutes atroom temperature and harvested by mechanical agitation in 10 mL of PBSsupplemented with 5 mM EDTA. Following resuspension, cells weretransferred to 40 mL fresh growth media for centrifugation for 5 minutesat 1000 rpm and resuspended in fresh growth medium at the appropriatesplit ratio.

For membrane preparation, cells were harvested by gentle mechanicalagitation with 5 mM EDTA in PBS followed by centrifugation (2500 g for 5minutes). The pellets were resuspended in Assay Buffer (50 mM4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acidN-(2-hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid) (HEPES)), pH7.4, and homogenized with a polytron disrupter on ice. The resultanthomogenates were centrifuged (1200 g for 5 minutes), the pelletsdiscarded and the supernatant centrifuged (40,000 g for 20 minutes). Thepellets were washed once by resuspension in Assay Buffer, followed by anadditional centrifugation (40,000 g for 20 minutes). The final pelletswere resuspended in Assay Buffer (equivalent 1 T-225 flask/1 mL assaybuffer). Protein concentration was determined using a Bio-Rad BradfordProtein Assay kit and membranes were stored in frozen aliquots at −80°C., until required.

Human delta opioid receptor (hDOP) membranes were purchased from PerkinElmer. The reported K_(d) and B_(max) for these membranes determined bysaturation analyses in a [³H]-Natrindole radioligand binding assays were0.14 nM (pK_(d)=9.85) and 2.2 pmol/mg protein, respectively. Proteinconcentration was determined using a Bio-Rad Bradford Protein Assay kit.Membranes were stored in frozen aliquots at −80° C., until required.

b. Radioligand Binding Assays

Radioligand binding assays were performed in an Axygen 1.1 mL deep well96-well polypropylene assay plate in a total assay volume of 200 μLcontaining the appropriate amount of membrane protein (˜3, ˜2 and ˜20 μgfor mu, delta and kappa, respectively) in Assay Buffer, supplementedwith 0.025% bovine serum albumin (BSA). Saturation binding studies fordetermination of K_(d) values of the radioligand were performed using[³H]-Diprenorphine at 8-12 different concentrations ranging from 0.001nM-5 nM. Displacement assays for determination of pKi values ofcompounds were performed with [³H]-Diprenorphine at 0.5, 1.2, and 0.7 nMfor mu, delta, and kappa, respectively, and eleven concentrations ofcompound ranging from 10 pM-100 μM.

Binding data were analyzed by nonlinear regression analysis with theGraphPad Prism Software package (GraphPad Software, Inc., San Diego,Calif.) using the 3-parameter model for one-site competition. The curveminimum was fixed to the value for nonspecific binding, as determined inthe presence of 10 μM naloxone. K_(i) values for test compounds werecalculated, in Prism, from the best fit IC₅₀ values, and the K_(d) valueof the radioligand, using the Cheng-Prusoff equation(K_(i)=IC₅₀/(1+([L]/K_(d))) where [L]=the concentration of[³H]-Diprenorphine Results are expressed as the negative decadiclogarithm of the K_(i) values, pK_(i).

Test compounds having a higher pK_(i) value in these assays have ahigher binding affinity for the mu, delta, or kappa opioid receptor. Thefinal compounds named in Examples 1-16 were tested in these assays. Allof the compounds had a pK_(i) value between about 8.7 and about 10.9 atthe human mu opioid receptor. For example, the compounds of Examples 1,9, 10-G, and 12 had pK_(i) values of 9.4, 9.2, 9.6, and 9.7,respectively. Compounds of the invention also exhibited pK_(i) valuesbetween about 7.5 and about 10.3 at the human delta and guinea pig kappaopioid receptors.

Assay 2: Agonist Mediated Activation of the Mu-Opioid Receptor inMembranes Prepared from CHO-K1 Cells Expressing the Human Mu-OpioidReceptor

In this assay, the potency and intrinsic activity values of testcompounds were determined by measuring the amount of bound [³⁵S]GTPγSpresent following receptor activation in membranes prepared from CHO-K1cells expressing the human mu opioid receptor.

a. Mu Opioid Receptor Membrane Preparation

Human mu opioid receptor (hMOP) membranes were either prepared asdescribed above or were purchased from Perkin Elmer. The reported pK_(d)and B_(max) for the purchased membranes determined by saturationanalyses in a [³H]-Diprenorphine radioligand binding assays was 10.06and 2.4 pmol/mg protein, respectively. Protein concentration wasdetermined using a Bio-Rad Bradford Protein Assay kit. Membranes werestored in frozen aliquots at −80° C., until required.

b. Human Mu [³⁵S]GTPγS Nucleotide Exchange Assay

Membranes were prepared as described above, and prior to the start ofthe assay, aliquots were diluted to a concentration of 200 μg/mL inAssay Buffer (50 mM HEPES, pH 7.4 at 25° C.), then homogenized for 10seconds using a Polytron homogenizer. Test compounds were received as 10mM stock solutions in DMSO, diluted to 400 μM into Assay Buffercontaining 0.1% BSA, and serial (1:5) dilutions then made to generateten concentrations of compound ranging from 40 pM-80 μM. GDP and[³⁵S]GTPγS were diluted to 40 μM and 0.4 nM, respectively, in AssayBuffer. The assay was performed in a total volume of 200 μL containing10 μg of membrane protein, test compound ranging from 10 pM-20 μM), 10μM GDP, and 0.1 nM [³⁵S]GTPγS diluted in 10 mM MgCl₂, 25 mM NaCl, and0.0125% BSA (final assay concentrations). A DAMGO(Tyr-D-Ala-Gly-(methyl)Phe-Gly-ol) concentration-response curve (rangingfrom 12.8 pM-1 μM) was included on every plate.

Assay plates were prepared immediately prior to assay following theaddition of 50 μL of the NaCl/MgCl₂/GDP solution, 50 μL of testcompound, and 50 μL of [³⁵S]GTPγS. The assay was initiated by theaddition of 50 μL of membrane protein and allowed to incubate for 30minutes at room temperature. The reaction was terminated by filtrationonto 96-well GF/B filter plates, pre-blocked with 0.3% polyethylenimine,using a Packard Filtermate harvester, and wash with ice-cold AssayBuffer (3×200 μl). Plates are dried overnight prior to determination ofcounts bound via liquid scintillation on a Packard Topcount instrument.Vehicle: DMSO not to exceed 1% final assay concentration.

The amount of bound [³⁵S]GTPγS is proportional to the degree ofactivation of the mu opioid receptors by the test compound. Theintrinsic activity (IA), expressed as a percentage, was determined asthe ratio of the amount of bound [³⁵S]GTPγS observed for activation bythe test compound to the amount observed for activation by DAMGO whichis presumed to be a full agonist (IA=100). All of the carboxylic acidcompounds of formula (I) were tested in this assay and demonstratedintrinsic activities of less than about 22. For example, the compoundsof Examples 1, 9, 10-G, and 12 had IA values of −8, −2, 7, and −5,respectively. In addition, the esters of Examples 2, 4, 5, 6, and 7-Aexhibited IA values of −5, 6, 17, 19, and 8, respectively. Thus,compounds of the present invention have been shown to act as antagonistsat the human mu opioid receptor.

Assay 3: Rat Model of In Vivo Efficacy

In this assay the efficacy of test compounds was evaluated in a model ofgastrointestinal transit, which evaluates peripheral activity. Thisstudy was approved by the Institutional Animal Care and Use Committee atTheravance, Inc. and conformed to the Guide for the Care and Use ofLaboratory Animals published by the National Academy of Sciences(©1996).

a. Rat Gastric Emptying Assay

Test compounds were evaluated in the rat gastric emptying assay todetermine their ability to reverse loperamide-induced delayed gastricemptying. Rats were fasted up overnight prior to administration of testcompounds or vehicle by intravenous, subcutaneous, intramuscular or oralroutes of administration at doses ranging from 0.001 to about 30milligrams/kilogram (mg/kg). The administration of test compound wasfollowed by subcutaneous administration of loperamide at a dose of 1mg/kg or vehicle. Five minutes post loperamide or vehicleadministration, a non-nutritive, non-absorbable charcoal meal wasadministered via oral gavage and animals were allowed free access towater for the sixty minute duration of the experiment. Animals were theneuthanized via carbon dioxide asphyxiation followed by thoracotomy andthe stomach was carefully excised. The stomach was ligated at the loweresophageal sphincter and the pyloric sphincter to prevent additionalemptying during tissue removal. Gastric weight was then determined afterremoval of the ligatures.

b. Data Analysis and Results

Data was analyzed using the GraphPad Prism Software package (GraphPadSoftware, Inc., San Diego, Calif.). Percent reversal curves wereconstructed by non-linear regression analysis using the sigmoidal doseresponse (variable slope) model and best-fit ID₅₀ values werecalculated. Curve minima and maxima were fixed to loperamide controlvalues (indicating 0% reversal) and vehicle controls (indicating 100%reversal), respectively. Results are expressed as ID₅₀, the doserequired for 50% reversal of the effects of loperamide, in milligramsper kilogram. The compounds of Examples 1, 9, 10-G, and 12 administeredorally, exhibited ID₅₀ values of 0.09 mg/kg, 0.10 mg/kg, 0.12 mg/kg, and0.05 mg/kg, respectively in the gastric emptying model.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation, material, composition of matter, process, processstep or steps, to the objective, spirit and scope of the presentinvention. All such modifications are intended to be within the scope ofthe claims appended hereto. Additionally, all publications, patents, andpatent documents cited hereinabove are incorporated by reference hereinin full, as though individually incorporated by reference.

1-6. (canceled)
 17. A compound of formula 2:

or a hydrobromide salt thereof, wherein R² and R³ are each independentlyC₁₋₃alkyl, and the substituents at the chiral centers marked byasterisks are in the trans configuration.
 18. A process for preparing ahydrobromide salt of a compound of formula 2 in solid form:

wherein R² and R³ are each independently C₁₋₃alkyl, and the substituentsat the chiral centers marked by asterisks are in the transconfiguration, the process comprising: (a) reacting a racemic mixture ofa compound of formula 1 and a compound having the oppositestereochemistry at the chiral centers:

wherein P¹ is C₁₋₃alkyl, with hydrogen bromide to form the hydrobromidesalt of the compound of formula 2; and (b) isolating the hydrobromidesalt of the compound of formula 2 in solid form.
 19. The process ofclaim 18 wherein step (a) is performed in the presence of a phasetransfer catalyst. 20-25. (canceled)
 26. The compound of claim 17wherein the compound is the hydrobromide salt of compound 2 in solidform.